阅读说明：本技术 检测发动机的气流分离的方法和设备 (Method and apparatus for detecting airflow separation of engine ) 是由 塞·文卡塔·凯思·莎丽贝拉 维士努·瓦德汉·文卡塔·塔提帕提 基思·布洛杰特 于 2021-04-27 设计创作，主要内容包括：公开了方法,设备,系统和制品,以检测发动机的气流分离。示例设备包括硬件和存储器,存储器包括指令,指令在被执行时使硬件至少：基于来自包括在涡轮风扇发动机的机舱中的第一压力传感器的第一压力值和来自包括在机舱中的第二压力传感器的第二压力值来确定入口流分离参数；基于入口流分离参数来确定严重性等级参数,严重性等级参数基于第一压力值和第二压力值之间的差；以及基于严重性等级参数来调节从涡轮风扇发动机的风扇后方的气流的贡献。(Methods, apparatus, systems, and articles of manufacture are disclosed to detect airflow separation of an engine. An example apparatus includes hardware and a memory including instructions that, when executed, cause the hardware to at least: determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of the turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter being based on a difference between the first pressure value and the second pressure value; and adjusting a contribution of airflow from behind a fan of the turbofan engine based on the severity-level parameter.)

1. An apparatus, comprising:

hardware; and

a memory comprising instructions that, when executed, cause the hardware to at least:

determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of a turbofan engine and a second pressure value from a second pressure sensor included in the nacelle;

determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter based on a difference between the first pressure value and the second pressure value; and

adjusting a contribution of airflow from behind a fan of the turbofan engine based on the severity level parameter.

2. The apparatus of claim 1, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the severity level parameter is a first severity level parameter, and the hardware:

determining an airflow direction at the outer lip based on a difference between the first pressure value and a threshold value;

determining a second severity level parameter based on the difference and a weight value; and

detecting inlet flow separation at an inlet of a turbofan engine based on the first severity level parameter and the second severity level parameter.

3. The apparatus of claim 2, wherein the hardware:

determining a first probability density function based on the first severity level parameter and the second severity level parameter;

comparing the first probability density function to a second probability density function stored in a database; and

detecting the inlet flow separation at the inlet of the turbofan engine based on the comparison.

4. The apparatus of claim 1, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the second pressure sensor is coupled to an inner lip of the nacelle, the severity level parameter corresponds to a nacelle inlet pressure differential, and the hardware:

determining the cabin inlet pressure differential based on a difference between the first pressure value and the second pressure value;

determining the severity level parameter based on the cabin inlet pressure differential and a weight value; and

detecting inlet flow separation at an inlet of a turbofan engine based on the severity level parameter.

5. The device of claim 1, wherein the severity level parameter is a first severity level parameter, and wherein the hardware:

obtaining acceleration data from an accelerometer coupled to a bearing of the turbofan engine;

determining a vibrational response of the turbofan engine based on the acceleration data;

determining a second severity level parameter based on the vibrational response and a weight value; and

detecting inlet flow separation at an inlet of a turbofan engine based on the first severity level parameter and the second severity level parameter.

6. The apparatus of any of claims 1-5, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the second pressure sensor is coupled to an inner lip of the nacelle, and the hardware:

obtaining altitude data and speed data from an aircraft coupled to the turbofan engine;

determining an air density based on the altitude data;

determining a Mach number based on the speed data; and

determining the inlet flow separation parameter based on at least one of the first pressure value, the second pressure value, the air density, or the Mach number.

7. The apparatus of any of claims 1-5, wherein the hardware adjusts the contribution of airflow from behind the fan by controlling an actuator included in the nacelle based on the severity-level parameter, the actuator moving from a first position to a second position to adjust the contribution of airflow from behind the fan to in front of the fan.

8. An apparatus, comprising:

an inlet flow separation parameter determiner that determines an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of a turbofan engine and a second pressure value from a second pressure sensor included in the nacelle;

an inlet flow separation severity level parameter determiner that determines a severity level parameter based on the inlet flow separation parameter, the severity level parameter based on a difference between the first pressure value and the second pressure value; and

a command generator that adjusts a contribution of airflow from behind a fan of the turbofan engine based on the severity level parameter.

9. The apparatus of claim 8, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the severity level parameter is a first severity level parameter, and the inlet flow separation severity level parameter determiner:

determining an airflow direction at the outer lip based on a difference between the first pressure value and a threshold value; and

determining a second severity level parameter based on the difference and a weight value; and further comprises

An inlet flow separation detector that detects inlet flow separation at an inlet of a turbofan engine based on the first severity level parameter and the second severity level parameter.

10. The apparatus of claim 9, wherein the inlet flow separation detector:

determining a first probability density function based on the first severity level parameter and the second severity level parameter;

comparing the first probability density function to a second probability density function stored in a database; and

detecting the inlet flow separation at the inlet of the turbofan engine based on the comparison.

Technical Field

The present disclosure relates generally to gas turbine engines and, more particularly, to methods and apparatus to detect airflow separation of an engine.

Background

Gas turbine engines typically include, in serial flow order, an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air enters the inlet section and flows to the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and combusted within the combustion section to produce combustion gases. The combustion gases flow from the combustion section through a hot gas path defined within the turbine section and then exit the turbine section via an exhaust section.

In a particular configuration, the compressor section includes, in serial flow order, a low pressure compressor ("LP compressor") and a high pressure compressor ("HP compressor"). The LP and HP compressors may include one or more axially spaced stages. Each stage may include a row of circumferentially spaced stator vanes and a row of circumferentially spaced rotor blades positioned downstream from the row of stator vanes. The stator vanes direct air flowing through the compressor section onto the rotor blades, which transfer kinetic energy to the air to increase its pressure.

The air intake of a gas turbine engine is subject to cross wind (cross wind) and high incident cross flow during takeoff in flight, which affects the air stability of the rotor blades. During such flight conditions, the airflow at the inlet of the gas turbine engine may separate, thereby causing inlet flow separation and reducing the performance of the gas turbine engine.

Disclosure of Invention

Methods and apparatus to control airflow separation for an engine are disclosed herein.

An example apparatus disclosed herein includes hardware and a memory, the memory including instructions that, when executed, cause the hardware to at least: determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of the turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter being based on a difference between the first pressure value and the second pressure value; and adjusting a contribution of airflow from behind a fan of the turbofan engine based on the severity-level parameter.

Another example apparatus disclosed herein includes: an inlet flow separation parameter determiner that determines an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of the turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; an inlet flow separation severity level parameter determiner that determines a severity level parameter based on the inlet flow separation parameter, the severity level parameter based on a difference between the first pressure value and the second pressure value; and a command generator that adjusts a contribution of airflow from behind a fan of the turbofan engine based on the severity level parameter.

An example non-transitory computer-readable storage medium disclosed herein includes instructions that, when executed, cause at least one processor to at least: determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of the turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter being based on a difference between the first pressure value and the second pressure value; and adjusting a contribution of airflow from behind a fan of the turbofan engine based on the severity-level parameter.

An example method disclosed herein includes: determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of a turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter being based on a difference between the first pressure value and the second pressure value; and adjusting a contribution of airflow from behind a fan of the turbofan engine based on the severity-level parameter.

Yet another example apparatus disclosed herein includes hardware and a memory including instructions that, when executed, cause the hardware to at least: determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of the turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; and determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter being based on a difference between the first pressure value and the second pressure value.

Drawings

FIG. 1 is a schematic cross-sectional view of a first example high bypass turbofan gas turbine engine.

FIG. 2 is a schematic cross-sectional view of the first example high bypass turbofan gas turbine engine of FIG. 1 during an inlet flow separation event.

FIG. 3 is a schematic cross-sectional view of a second example high bypass turbofan gas turbine engine including an example controller to monitor inlet flow separation using an example pressure sensor.

FIG. 4A is a schematic cross-sectional view of a third example high bypass turbofan gas turbine engine that includes the example controller and example actuator of FIG. 3 to adjust a contribution of airflow to an inlet section of the third high bypass turbofan gas turbine engine.

FIG. 4B is a schematic cross-sectional view of a fourth example high bypass turbofan gas turbine engine that includes the example controller and the example pressure sensor of FIG. 3 and the example actuator to adjust a contribution of airflow to an inlet section of the fourth high bypass turbofan gas turbine engine.

FIG. 5 is a schematic cross-sectional view of the fourth example high bypass turbofan gas turbine engine of FIG. 4B during an inlet flow separation event.

FIG. 6 is a block diagram of an embodiment of an example controller for use with the high bypass turbofan gas turbine engine of FIGS. 3-5.

FIG. 7 is a table depicting example determinations for detecting inlet flow separation for the high bypass turbofan gas turbine engine of FIGS. 3-5.

FIG. 8 is a flow diagram representing example machine readable instructions that may be executed to implement the example controllers of FIGS. 3-6 to adjust airflow contributions to an inlet of the high bypass turbofan gas turbine engine of FIGS. 4A-5.

FIG. 9 is a flow diagram representing example machine readable instructions that may be executed to implement the controller of FIGS. 3-6 to determine an inlet flow separation parameter based on sensor data associated with the high bypass turbofan gas turbine engine of FIGS. 3-5.

FIG. 10 is a flow diagram representing example machine readable instructions that may be executed to implement the controller of FIGS. 3-6 to detect inlet flow separation based on example inlet flow separation parameters.

FIG. 11 is a flowchart representative of example machine readable instructions that may be executed to implement the controller of FIGS. 3-6 to identify an example inlet flow separation control measure based on an example inlet flow separation severity level parameter.

FIG. 12 is a flow diagram representing example machine readable instructions that may be executed to implement the controller of FIGS. 3-6 to adjust airflow contribution to an inlet of the high bypass turbofan gas turbine engine of FIGS. 4A, 4B, and/or 5.

Fig. 13 is a block diagram of an example processing platform configured to execute the machine readable instructions of fig. 8-12 to implement the controller of fig. 3-6.

The figures are not drawn to scale. Generally, the same reference numbers will be used throughout the drawings and the following written description to refer to the same or like parts.

Detailed Description

The descriptors "first", "second", "third", etc. are used herein when identifying a plurality of elements or components that may be referenced separately. Unless otherwise stated or understood based on its context of use, such descriptors are not intended to be given any meaning in priority, physical order or arrangement in a list, or temporal order, but rather are used merely as labels to refer to a plurality of elements or components, respectively, for ease of understanding of the disclosed examples. In some examples, the descriptor "first" may be used to refer to an element in the detailed description, while a different descriptor, such as "second" or "third," may be used in the claims to refer to the same element. In such cases, it should be understood that such descriptors are used only for ease of reference to a number of elements or components.

As used herein, the terms "upstream" and "downstream" refer to relative directions with respect to fluid flow in a fluid path. For example, "upstream" refers to the direction from which the fluid flows, while "downstream" refers to the direction to which the fluid flows.

The performance of gas turbine engines used on aircraft (e.g., commercial aircraft) varies during different flight conditions experienced by the aircraft. In some cases, adverse (overture) flight conditions may degrade the performance of the gas turbine engine. Such adverse flight conditions may include takeoff of the aircraft or crosswind conditions of the aircraft in flight. The inlet lip (lip) section located at the forward most end of the engine nacelle is typically designed to enable the engine to operate to prevent separation of the airflow from the inlet lip section of the nacelle during adverse flight conditions. As used herein, the separation of the airflow from the inlet lip section of the nacelle is referred to as "inlet flow separation" or "inlet airflow separation" and is used interchangeably. For example, the inlet lip section may require a "thick" inlet lip section design to support operation of the engine during certain flight conditions (e.g., crosswind conditions, take-off, etc.).

In some cases, inlet flow separation can result in a significant asymmetry in the total pressure within the engine intake. In such a case, the asymmetric total pressure may result in asymmetric loading of the fan blades of the engine fan, which may increase the stress of the fan blades. In some such cases, the stress of the fan blades may result in a reduction in the reliability and/or operating life of the fan blades and/or more generally the engine. Some severe cases of inlet flow separation may cause compressor or engine surge, which is an increase in the revolutions per minute (rpm) of the engine compressor. For example, severe inlet flow separation may cause the compressor and/or more generally the engine to stall.

Reference now will be made in detail to embodiments of the disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not limitation of the disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit thereof. For example, features illustrated or described as part of one example may be used with another example to yield a still further example. Thus, it is intended that the present disclosure cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Examples disclosed herein detect and control airflow separation for an engine, such as a gas turbine engine. In some disclosed examples, an Inlet Flow Separation (IFS) controller determines one or more severity level parameters or IFS severity level parameters that may be used to detect IFS. For example, the IFS controller may determine a first IFS severity level parameter based on an airflow direction, a second IFS severity level parameter based on a pressure differential across an inlet section of the engine compartment, and/or a third IFS severity level parameter based on an engine vibration response. In such an example, the IFS controller may determine the first IFS severity level parameter and/or the second IFS severity level parameter based on air pressure data from an air pressure sensor included in an inlet lip section of the nacelle, an outlet lip section of the nacelle, or the like. In some such examples, the IFS controller may determine the third IFS severity level parameter based on acceleration data obtained from one or more acceleration sensors monitoring one or more bearings (e.g., ball bearings, roller bearings, etc.) of the engine.

In some disclosed examples, the IFS controller may determine an IFS severity level or degree or quantification of IFS (if any) at the engine inlet based on the IFS severity level parameter. For example, the IFS controller may determine the probability density function based on the IFS severity level parameter. In such an example, the IFS controller may detect IFS at the engine inlet by comparing the probability density function to one or more stored probability density functions, which may correspond to a characterization or representation of the engine under a plurality of flight conditions.

In some disclosed examples, in response to detecting an IFS, the IFS controller may control one or more actuators included in the engine compartment to reduce and/or otherwise eliminate the detected IFS. For example, the IFS controller may control the actuator to adjust (1) a first airflow contribution from a first area behind the engine fan to (2) a third area in front of the fan, and/or to adjust (1) a second airflow contribution from a second area of the engine core to (2) a third area in front of the fan. In such an example, the IFS controller may reduce and/or otherwise eliminate the IFS by adjusting an airflow contribution of at least one of the first zone or the second zone. Advantageously, examples disclosed herein may reduce and/or otherwise eliminate IFS by adjusting the airflow contribution from at least one of the first or second regions to the third region, thereby improving the reliability and operating life of the engine.

As used herein, "including" and "comprising" (and all forms and tenses thereof) are open-ended terms. Thus, whenever a claim recites "comprising" or "including" (e.g., comprising, including, having, etc.) in any form thereof as a preface or in the recitation of any kind of claim, it should be understood that other elements, terms, etc. may be present without departing from the scope of the corresponding claim or recitation. As used herein, the phrase "at least" when used as a transitional term, such as in the preamble of a claim, is open-ended in the same manner that the terms "comprising" and "including" are open-ended. When used, for example, in a format such as a, B, and/or C, the term "and/or" refers to any combination or subset of a, B, C, such as (1) a only, (2) B only, (3) C only, (4) a and B, (5) a and C, (6) B and C, and (7) a and B and C. As used herein in the context of describing structures, components, articles, objects, and/or things, the phrase "at least one of a and B" is intended to refer to embodiments that include any one of (1) at least one a, (2) at least one B, and (3) at least one a and at least one B. Similarly, as used herein in the context of describing structures, components, articles, objects, and/or things, the phrase "at least one of a or B" is intended to refer to embodiments that include any one of (1) at least one a, (2) at least one B, and (3) at least one a and at least one B. As used herein in the context of describing the performance or execution of processes, instructions, actions, activities, and/or steps, the phrase "at least one of a and B" is intended to refer to embodiments that include any of (1) at least one a, (2) at least one B, and (3) at least one a and at least one B. Similarly, as used herein in the context of describing the performance or execution of processes, instructions, actions, activities, and/or steps, the phrase "at least one of a or B" is intended to refer to embodiments that include any of (1) at least one a, (2) at least one B, and (3) at least one a and at least one B.

As used herein, singular references (e.g., "a," "an," "first," "second," etc.) do not exclude a plurality. As used herein, the term "a" or "an" entity refers to one or more of that entity. The terms "a" (or "an"), "one or more" and "at least one" are used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements or method acts may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different examples or claims, these may be combined, and the inclusion in different examples or claims does not imply that a combination of features is not feasible and/or advantageous.

Referring now to the drawings, in which like numerals refer to like elements throughout the several views, FIG. 1 is a schematic cross-sectional view of a first example high bypass turbofan gas turbine engine 100 ("turbofan engine 100") that may incorporate various examples disclosed herein. As shown in FIG. 1, first turbofan engine 100 defines a longitudinal or axial centerline axis 102 extending therethrough for reference. Generally, the first turbofan engine 100 may include a core turbine or gas turbine engine 104 disposed downstream of a fan section 106.

The core turbine engine 104 may generally include a substantially tubular casing 108 defining an annular inlet 110. The housing 108 may be formed of a single shell or multiple shells. The housing 108 encloses in serial flow relationship: a compressor section having a booster or low pressure compressor 112 ("LP compressor 112") and a high pressure compressor 114 ("HP compressor 114"); a combustion section 116; a turbine section having a high pressure turbine 118 ("HP turbine 118") and a low pressure turbine 120 ("LP turbine 120"); and an exhaust section 122. A high pressure shaft or spool 124 ("HP shaft 124") drivingly couples the HP turbine 118 and the HP compressor 114. A low pressure shaft or spool 126 ("LP shaft 126") drivingly couples LP turbine 120 and LP compressor 112. The LP shaft 126 may also be coupled to a fan shaft or spool 128 of the fan section 106. In some examples, the LP shaft 126 may be directly coupled to the fan shaft 128 (i.e., a direct drive configuration). In an alternative configuration, the LP shaft 126 may be coupled to the fan shaft 128 via a reduction gear 130 (i.e., an indirect drive or gear drive configuration).

As shown in FIG. 1, fan section 106 includes a plurality of fan blades 132 ("fan" 132), the plurality of fan blades 132 coupled to fan shaft 128 and extending radially outward from fan shaft 128. A first annular fan casing or first nacelle 134 circumferentially surrounds at least a portion of fan section 106 and/or core turbine 104. The first turbofan engine 100 includes a second nacelle 135 opposite the first nacelle 134. The nacelles 134, 135 may be supported relative to the core turbine 104 by a plurality of circumferentially spaced outlet guide vanes 136. Further, a downstream section 138 of the nacelles 134, 135 may surround an outer portion of the core turbine 104 to define a bypass airflow passage 140 therebetween.

As shown in FIG. 1, air 142 enters an air intake or inlet portion 144 of the first turbofan engine 100 during operation of the first turbofan engine 100. A first portion 146 of the air 142 flows into the bypass airflow path 140, and a second portion 148 of the air 142 flows into the inlet 110 of the LP compressor 112. One or more sequential stages of LP compressor stator vanes 150 and LP compressor rotor blades 152 coupled to the LP shaft 126 gradually compress a second portion 148 of the air 142 flowing through the LP compressor 112 that is channeled to the HP compressor 114. Next, one or more sequential stages of HP compressor stator vanes 154 and HP compressor rotor blades 156 coupled to HP shaft 124 further compress second portion 148 of air 142 flowing through HP compressor 114. This provides compressed air 158 to combustion section 116, where compressed air 158 is mixed with fuel and combusted to provide combustion gases 160 in combustion section 116.

The combustion gases 160 flow through the HP turbine 118, where one or more sequential stages of HP turbine stator vanes 162 and HP turbine rotor blades 164 coupled to the HP shaft 124 extract a first portion of kinetic and/or thermal energy from the combustion gases 160. This energy extraction supports the operation of the HP compressor 114. The combustion gases 160 then flow through the LP turbine 120, where one or more sequential stages of LP turbine stator vanes 166 and LP turbine rotor blades 168 coupled to the LP shaft 126 extract a second portion of the thermal and/or kinetic energy from the combustion gases 160 in the LP turbine 120. This energy extraction rotates the LP shaft 126, thereby supporting operation of the LP compressor 112 and/or rotation of the fan shaft 128. The combustion gases 160 then exit the core turbine 104 through the exhaust section 122 of the core turbine 104.

Along with the first turbofan 100, the core turbine 104 functions similarly, and in land-based gas turbine engines, turbojet engines in which the ratio of the first portion 146 of air 142 to the second portion 148 of air 142 is less than that of a turbofan, and similar environments are found in non-ducted fan engines in which the fan section 106 does not have nacelles 134, 135. In each of the turbofan, turbojet and non-ducted engines, a reduction device (e.g., reduction gearbox 130) may be included between any of the shafts and spools. For example, the reduction gearbox 130 may be disposed between the LP shaft 126 and the fan shaft 128 of the fan section 106.

As depicted therein, the first turbofan engine 100 defines an axial direction a, a radial direction R, and a circumferential direction C. Generally, axial direction a extends generally parallel to axial centerline axis 102, radial direction R extends orthogonally outward from axial centerline axis 102, and circumferential direction C extends concentrically about axial centerline axis 102.

FIG. 2 is a schematic cross-sectional view of the first high bypass turbofan gas turbine engine 100 of FIG. 1 during an Inlet Flow Separation (IFS) event. In FIG. 2, the IFS event is represented by an example arrow 202, the example arrow 202 moving toward a middle or middle section of the fan section 106 of FIG. 1 and/or more generally toward the axial centerline axis 102 of FIG. 1. For example, arrows 202 may represent air 142 separated at an inlet section (e.g., nacelle inlet section) 204, 206 of the nacelle 134, 135 of fig. 1. In such examples, the IFS event may cause an asymmetry in the pressure (e.g., air pressure) experienced by fan blades 132 and/or a portion of fan section 106 of fig. 1.

In FIG. 2, an IFS event may be caused by an example adverse flight condition. For example, first turbofan engine 100 may be coupled to an aircraft and may cause an IFS event in response to takeoff of the aircraft. In other examples, first turbofan engine 100 may be coupled to an aircraft and may cause an IFD event in response to a crosswind (e.g., a crosswind condition, a crosswind event, etc.) while the aircraft is in flight.

In fig. 2, the nacelle inlet sections 204, 206 comprise a first nacelle inlet section 204 and a second nacelle inlet section 206. In fig. 2, the first nacelle inlet section 204 has a first outer lip (lip) (e.g., a first outer lip surface, a first outer lip section, etc.) 208 and a first inner lip (e.g., a first inner lip surface, a first inner lip section, etc.) 210. In fig. 2, second nacelle inlet section 206 has a second outer lip (e.g., a second outer lip surface, a second outer lip section, etc.) 212 and a second inner lip (e.g., a second inner lip surface, a second inner lip section, etc.) 214.

In some examples, fan blades 132 are subjected to stresses (e.g., mechanical stresses, vibrational stresses, etc.) in response to an IFS event. In response to the stress, one or more fan blades 132 may structurally degrade, weaken, etc. over time and may result in a reduction in the reliability and/or operating life of the fan blades 132. For example, one or more fan blades 132 may be damaged in response to an IFS event.

In some examples, the IFS event may cause a significant asymmetry in pressure at the inlet portion 144 of FIG. 1, which may result in compressor or engine surge. For example, at least one of the LP compressor 112 or the HP compressor 114 may experience compressor surge in response to an IFS event. In such an example, compressor surge may cause at least one of the LP compressor 112 or the HP compressor 114 to stall, and/or more generally may cause the core turbine 104 of FIGS. 1-2 to stall.

FIG. 3 is a schematic cross-sectional view of a second example high bypass turbofan gas turbine engine 300 that includes an example controller (e.g., an IFS controller) that monitors inlet flow separation using example pressure sensors 304, 306, 308, 310. The second turbofan engine 300 may be an exemplary embodiment of the first turbofan engine 100 of fig. 1-2. For example, the second turbofan engine 300 may include all of the components of the first turbofan engine 100 of fig. 1, such as the gas turbine engine 104, the tubular casing 108, the LP compressor 112, the HP compressor 114, and so forth of fig. 1-2. In such an example, the description in connection with the first turbofan engine 100 of FIGS. 1-2 may apply to the second turbofan engine 300 of FIG. 3.

In fig. 3, IFS controller 302 is a Full Authority Digital Engine Control (FADEC) unit. Alternatively, the IFS controller 302 may be an Engine Control Unit (ECU), an Electronic Engine Control (EEC) unit, or the like, or any other type of data acquisition and/or control computing device, processor platform (e.g., a processor-based computing platform), or the like. In fig. 3, the IFS controller 302 is included in the second nacelle 135. Alternatively, IFS controller 302 may be included at any other location of second turbofan engine 300 (e.g., first nacelle 134).

In FIG. 3, pressure sensors 304, 306, 308, 310 include a first example pressure sensor 304, a second example pressure sensor 306, a third example pressure sensor 308, and a fourth example pressure sensor 310. In fig. 3, the first pressure sensor 304 is coupled to the first outer lip 208 of the first nacelle 134. In fig. 3, the second pressure sensor 306 is coupled to the first inner lip 210 of the first nacelle 134. The first pressure sensor 304 is configured to measure a first air pressure at the first outer lip 208. During an IFS event (e.g., the IFS event depicted in fig. 2-3), the first air pressure may approximate a stagnation pressure. The second pressure sensor 306 is configured to measure a second air pressure at the first inner lip 210. In fig. 3, the second gas pressure may approximate the static pressure.

In FIG. 3, third pressure sensor 308 is coupled to second outer lip 212 of second nacelle 135. In FIG. 3, a fourth pressure sensor 310 is coupled to second inner lip 214 of second nacelle 135. The third pressure sensor 308 is configured to measure a third air pressure at the second outer lip 212. During an IFS event (such as the IFS event depicted in FIGS. 2-3), the third air pressure may approximate the stagnation pressure. The fourth pressure sensor 310 is configured to measure a fourth air pressure at the second inner lip 214. In fig. 3, the fourth air pressure may be approximated by the static pressure.

In fig. 3, the first pressure sensor 304, the second pressure sensor 306, the third pressure sensor 308, and the fourth pressure sensor 310 are wireless sensors (e.g., wireless pressure sensors, wireless piezoelectric pressure sensors, wireless passive piezoelectric pressure sensors, etc.). For example, first pressure sensor 304, second pressure sensor 306, third pressure sensor 308, and fourth pressure sensor 310 may be wireless passive piezoelectric pressure sensors. Alternatively, one or more of first pressure sensor 304, second pressure sensor 306, third pressure sensor 308, and/or fourth pressure sensor 310 may be a wired pressure sensor (e.g., a wired pressure sensor, a wired piezoelectric pressure sensor, a wired passive piezoelectric pressure sensor, etc.). Alternatively, one or more of first pressure sensor 304, second pressure sensor 306, third pressure sensor 308, and/or fourth pressure sensor 310 may be a different type of sensor, such as a diaphragm pressure sensor, a pitot tube, or the like.

In fig. 3, the first pressure sensor 304 and the second pressure sensor 306 are communicatively coupled to a first example antenna (e.g., antenna module) 312. In FIG. 3, the third pressure sensor 308 and the fourth pressure sensor 310 are communicatively coupled to a second example antenna 314. In fig. 3, a first antenna 312 is included in the first nacelle 134 and a second antenna 314 is included in the second nacelle 135. Alternatively, two antennas 312, 314 may be included in the first nacelle 134, while in other examples, two antennas 312, 314 may be included in the second nacelle 135.

In fig. 3, first antenna 312 and second antenna 314 are coupled (e.g., communicatively coupled, electrically coupled, etc.) to IFS controller 302 via a wired connection (not shown). Alternatively, one or both of antennas 312, 314 may be coupled to IFS controller 302 via a wireless connection. In an example operation, the first pressure sensor 304 and the second pressure sensor 306 may transmit pressure data (e.g., barometric pressure data, barometric pressure measurements, etc.) to the IFS controller 302 via the first antenna 312. In an example operation, the third pressure sensor 308 and the fourth pressure sensor 310 may transmit pressure data (e.g., barometric pressure data, barometric pressure measurements, etc.) to the IFS controller 302 via the second antenna 314.

In FIG. 3, turbofan engine 300 includes example acceleration sensors 316, 318 in an example bearing section 320. In fig. 3, the bearing segment 320 includes, corresponds to and/or otherwise represents example bearings 317, 319 (e.g., ball bearings, roller bearings, etc.) to support the fan shaft 128. In fig. 3, acceleration sensors 316, 318 are coupled to a bearing section 320 (e.g., to one or more bearings 317, 319 included in bearing section 320) to monitor and/or otherwise measure forces (e.g., acceleration forces, vibrational forces, etc.) experienced by the bearings.

In fig. 3, the acceleration sensors 316, 318 include a first example acceleration sensor 316 and a second example acceleration sensor 318. In fig. 3, the acceleration sensors 316, 318 are accelerometers. For example, one or more of the acceleration sensors 316, 318 may be a vibration sensor (e.g., a vibration sensor including a piezoelectric crystal element), a gyroscope sensor, or a velocity sensor. In fig. 3, a first acceleration sensor 316 is coupled to a first side of the fan shaft 128. In fig. 3, the first acceleration sensor 316 is coupled to a first example bearing 317 that includes bearings 317, 319 in a bearing section 320. In fig. 3, a second acceleration sensor 318 is coupled to a second side of the fan shaft 128, where the second side is on an opposite side of the axial centerline axis 102. In fig. 3, the second acceleration sensor 318 is coupled to a second example bearing 319 of the bearings 317, 319 included in the bearing section 320.

FIG. 4A is a schematic cross-sectional view of a third example high bypass turbofan gas turbine engine 400 that includes the IFS controller 302 and the antennas 312, 314 of FIG. 3. Alternatively, third turbofan engine 400 may not include one or both of antennas 312, 314. The third turbofan engine 400 may be an exemplary embodiment of the first turbofan engine 100 of fig. 1-2 or a portion thereof, and/or the second turbofan engine 300 of fig. 3 or a portion thereof. For example, the third turbofan engine 400 may include one or more components of the first turbofan engine 100 of fig. 1-2 and/or the second turbofan engine 300 of fig. 3, such as the gas turbine engine 104, the tubular casing 108, the LP compressor 112, the HP compressor 114, etc. of fig. 1-3, the IFS controller 302 of fig. 3, the antennas 312, 314, etc., and/or combinations thereof. In such examples, the description in connection with the first turbofan engine 100 of fig. 1-2 and/or the description in connection with the second turbofan engine 300 of fig. 3 may be applicable to the third turbofan engine 400 of fig. 4A.

In fig. 4A, a third turbofan engine 400 includes example actuators 402, 404 to regulate a contribution of airflow from at least one of a first example section (e.g., a first airflow section, a first airflow contribution section, a first airflow portion, a first airflow region, etc.) 406 or a second example section (e.g., a second airflow section, a second airflow contribution section, a second airflow portion, a second airflow region, etc.) 408 to a third example section (e.g., a third airflow section, a third airflow contribution section, a third airflow portion, a third airflow region, etc.) 410. In fig. 4A, the actuators 402, 404 include: a first example actuator 402 included in the first nacelle 134; and a second example actuator 404 included in the second nacelle 135.

In FIG. 4A, the first section 406 corresponds to the airflow section between the LP compressor 112 and the HP compressor 114, and may be generally referred to herein as the "core". In FIG. 4A, the second section 408 may correspond to the airflow section behind fan blades 132 and in front of outlet guide vanes 136. In fig. 4A, the third section 410 may correspond to the airflow section in front of the fan blades 132. For example, the third section 410 may include, correspond to, and/or otherwise represent the fan section 106.

In fig. 4A, the gas flow sections 406, 408, 410 are fluidly coupled and/or otherwise connected via example conduits (e.g., gas flow conduits, exhaust channels, exhaust passages, etc.) 412, 414. For example, the airflow from the first section 406 and/or the second airflow section 408 may be directed, etc., to the third airflow section 410 via conduits 412, 414. The conduits 412, 414 include: a first example duct 412 included in the first nacelle 134; and a second example duct 414 included in the second nacelle 135. In FIG. 4A, the conduits 412, 414 are constructed of the same material and/or otherwise constructed as the nacelles 134, 135. For example, the conduits 412, 414 may be constructed from one or more composite materials, one or more metallic materials, the like, and/or combinations thereof.

In fig. 4A, the first conduit 412 has a first opening (e.g., a first conduit opening) 416, a second opening 418 (e.g., a second conduit opening), and a third opening (e.g., a third conduit opening) 420. The first opening 416 of the first conduit 412 is a first inlet (e.g., a first conduit inlet) coupled to the first section 406. The first opening 416 of the first conduit 412 is configured to obtain a flow of gas (e.g., a pressurized flow of gas) from the first section 406. The second opening 418 of the first conduit 412 is a second inlet (e.g., a second conduit inlet) coupled to the second section 408. The second opening 418 of the first conduit 412 is configured to obtain a flow of gas (e.g., ambient gas flow, non-pressurized gas flow, incoming gas flow, etc.) from the second section 408. The third opening 420 of the first conduit 412 is an outlet (e.g., a conduit outlet) coupled to the third section 410. The third opening 420 of the first conduit 412 is configured to discharge and/or otherwise output a gas flow to the third section 410.

In fig. 4A, the second conduit 414 has a first opening (e.g., a first conduit opening) 422, a second opening 424 (e.g., a second conduit opening), and a third opening (e.g., a third conduit opening) 426. The first opening 422 of the second conduit 414 is a first inlet (e.g., a first conduit inlet) coupled to the first section 406. The first opening 422 of the second conduit 414 is configured to obtain airflow from the first section 406. The second opening 424 of the second conduit 414 is a second inlet (e.g., a second conduit inlet) coupled to the second section 408. The second opening 424 of the second conduit 414 is configured to obtain airflow from the second section 408. The third opening 426 of the second conduit 414 is an outlet (e.g., a conduit outlet) coupled to the third section 410. The third opening 420 of the second conduit 414 is configured to discharge and/or otherwise output a gas flow to the third section 410.

In fig. 4A, the airflow (e.g., exhaust airflow) from the conduits 412, 414 is exhausted in a direction opposite to the direction of the air 142 (e.g., the air 142 that is oncoming at the inlet portion 144), is introduced, and waits into the third section 410. The exhaust flow introduced into the third section 410 from the conduits 412, 414 forces the air 142 to flow around the exhaust flow. Advantageously, the exhaust flow introduced to the third section 410 simulates and/or otherwise acts as a "thick" nacelle lip to reduce and/or otherwise eliminate IFS at the inlet portion 144.

In fig. 4A, the gas flow from conduits 412, 414 may be taken from the first section 406 and/or the second section 408 and may therefore be delivered to the third section 410 at a relatively high pressure. The air flow from the conduits 412, 414 is introduced into the third section 410 at an angle relative to the air 142. Alternatively, the airflow from the ducts 412, 414 may be directed into the third section 410 at any angle based on the design of the nacelle 134, 135 and/or, more generally, the third turbofan engine 400.

In fig. 4A, the actuators 402, 404 are solenoid actuated and/or otherwise controlled valves. Alternatively, the actuators 402, 404 may be any other type of actuator. The actuators 402, 404 are operable in at least three positions including a first position, a second position, and a third position. The first, second, and third positions may correspond to the amount of opening of the actuators 402, 404 to the different sections 406, 408, 410. For example, the actuators 402, 404 in the first position may direct a large amount of air from the first section 406 to the third section 410 and a small amount of air from the second section 408 to the third section 410. In such an example, the first position may correspond to the actuators 402, 404 being 70%, 80%, 90%, etc. open to the first section 406 and 30%, 20%, 10%, etc. open to the second section 408.

In other examples, the actuators 402, 404 in the second position may direct a moderate amount of air from the first section 406 to the third section 410 and a moderate amount of air from the second section 408 to the third section 410. In such an example, the second position may correspond to the actuators 402, 404 being open 45%, 50%, 55%, etc. to the first section 406 and 55%, 50%, 45%, etc. to the second section 408.

In still other examples, the actuators 402, 404 in the third position may direct a small amount of air from the first section 406 to the third section 410 and a large amount of air from the second section 408 to the third section 410. In such an example, the third position may correspond to the actuators 402, 404 being 10%, 20%, 30%, etc. open to the first section 406 and 90%, 80%, 70%, etc. open to the second section 408. For example, a small amount of air is less than a moderate amount of air, which is less than a large amount of air.

In fig. 4A, the first antenna 312 is coupled to the first actuator 402 via a wired connection, and the second antenna 314 is coupled to the second actuator 404 via a wired connection. Alternatively, the first antenna 312 may be coupled to the first actuator 402 via a first wireless connection and/or the second antenna 314 may be coupled to the second actuator 404 via a second wireless connection. For example, the IFS controller 302 of fig. 3 may transmit wireless commands, directions, instructions, etc. to one or more of the antennas 312, 314 to control one or more of the actuators 402, 404 to change position. By invoking the actuators 402, 404 to change positions, the airflow contribution from at least one of the first section 406 or the second section 408 to the third section 410 may be adjusted. Advantageously, by adjusting the airflow contribution to first section 406, IFS controller 302 may reduce and/or otherwise eliminate IFS in response to adverse flight conditions of third turbofan engine 400.

Advantageously, the IFS controller 302 may reduce and/or otherwise eliminate IFS by delivering a pressurized airflow (e.g., airflow from the first section 406), an ambient airflow (e.g., airflow from the second section 408), and/or the like, and/or combinations thereof, to the third section 410. For example, in response to detecting a first severity level of the IFS, the IFS controller 302 may convey a first portion of ambient air from the second section 408 to the third section 410. In such an example, in response to the second severity level of the detected IFS being greater than the first severity level of the detected IFS (e.g., the second severity level representing a greater or more severe IFS than the first severity level), the IFS controller 302 may (1) convey the second portion of ambient air from the second section 408 to the third section 408 and/or (2) convey the third portion of pressurized air from the first section 406 to the third section 408. In some such examples, the second portion of ambient air may be smaller and/or otherwise different than the first portion of ambient air.

FIG. 4B is a schematic cross-sectional view of a fourth example high bypass turbofan gas turbine engine 430 that includes the IFS controller 302 of FIGS. 3-4A, the pressure sensors 304, 306, 308, 310 of FIG. 3, and the antennas 312 and 314 of FIGS. 3-4A. The fourth turbofan engine 430 may be an exemplary embodiment of the first turbofan engine 100 or portion thereof of fig. 1-2, the second turbofan engine 300 or portion thereof of fig. 3, and/or the third turbofan engine 400 or portion thereof of fig. 4A. For example, fourth turbofan engine 430 may include one or more components of first turbofan engine 100 of fig. 1-2, second turbofan engine 300 of fig. 3, and/or third turbofan engine 400 of fig. 4A, such as gas turbine engine 104, tubular casing 108, LP compressor 112, HP compressor 114, etc. of fig. 1-3, IFS controller 302 of fig. 3, pressure sensors 304, 306, 308, 310, antennas 312, 314, etc., and/or combinations thereof. In such an example, the description in connection with the first turbofan engine 100 of fig. 1-2, the description in connection with the second turbofan engine 300 of fig. 3, and/or the description in connection with the third turbofan engine 400 of fig. 4A may be applicable to the fourth turbofan engine 430 of fig. 4B.

In fig. 4B, the IFS controller 302, the first pressure sensor 304, and the second pressure sensor 306 are in communication with the first antenna 312 via a wireless connection and/or otherwise communicatively coupled to the first antenna 312. In fig. 4B, the first actuator 402 is in communication with the first antenna 312 via a wired connection and/or otherwise communicatively coupled to the first antenna 312. Alternatively, the first actuator 402 may be in communication with the first antenna 312 via a wireless connection and/or otherwise communicatively coupled to the first antenna 312.

In fig. 4B, the IFS controller 302, the third pressure sensor 308, and the fourth pressure sensor 310 are in communication with the second antenna 314 via a wireless connection and/or are otherwise communicatively coupled to the second antenna 314. In fig. 4B, the second actuator 404 is in communication with the second antenna 314 via a wired connection and/or otherwise communicatively coupled to the second antenna 314. Alternatively, the second actuator 404 may be in communication with the second antenna 314 via a wireless connection and/or otherwise communicatively coupled to the second antenna 314.

In fig. 4B, fourth turbofan engine 430 includes IFS controller 302 to detect an IFS at inlet portion 144 based on pressure measurements from at least one of first pressure sensor 304, second pressure sensor 306, third pressure sensor 308, or fourth pressure sensor 310. In fig. 4B, IFS controller 302 may obtain pressure measurements from one or more of pressure sensors 304, 306, 308, 310 via respective one or more of antennas 312, 314. In fig. 4B, the IFS controller 302 may control one or more of the actuators 402, 404 based on the IFS detection. For example, the IFS controller 302 may generate and transmit commands to the first actuator 402 and/or the second actuator 404. In such an example, in response to obtaining the command, the first actuator 402 may move from the first position to the second position, the second actuator 404 may move from the third position to the fourth position, and so on. In some such examples, movement of the first actuator 402 and/or the second actuator 404 may adjust the airflow contribution from at least one of the first segment 406 or the second segment 408 to the third segment 410.

FIG. 5 is a schematic cross-sectional view of the fourth high bypass turbofan gas turbine engine 430 of FIG. 4B during an inlet flow separation event. In fig. 5, two different air streams 502, 504 are depicted, including a first air stream 502 and a second air stream 504. The first airflow 502 corresponds to a separation of the air 142 incident to the nacelle inlet sections 204, 206, which causes the air 142 to move toward the axial centerline axis 102. The first airflow 502 may result in compressor or engine surge, increased engine vibration response, etc., and/or combinations thereof, which may result in reduced reliability and/or operational life of the fan blades 132 or any other component of the third turbofan engine 400.

In fig. 5, the second airflow 504 corresponds to an example in which separation of the air 142 incident to the nacelle inlet sections 204, 206 does not occur and/or is otherwise minimized. For example, the second airflow 504 may correspond to an IFS event represented by arrow 202 of fig. 2. In fig. 5, the second airflow 504 flows along the inner lips 210, 214 of the third turbofan engine 400. For example, in response to the IFS controller 302 detecting the first airflow 502 (e.g., detecting an IFS event), the IFS controller 302 may control one or more of the actuators 402, 404 of fig. 4A and/or 4B to discharge airflow from at least one of the first section 406 or the second section 408 to the third section 410. Advantageously, the IFS controller 302 may adjust the first airflow 502 to the second airflow 504 in response to adjusting the airflow contribution from at least one of the first section 406 or the second section 408 to the third section 410.

Fig. 6 is a block diagram of an embodiment of the IFS controller 302 of fig. 3-5. IFS controller 302 is configured to detect and/or control an IFS at inlet 144 of turbofan engine 300, 400, 430 of FIGS. 3-5. In response to detecting the IFS, the IFS controller 302 is configured to control one or more of the actuators 402, 404 of fig. 4-5 to control a contribution from at least one of the core (e.g., the first section 406 of fig. 4-5) or behind the fan 132 (e.g., the second section 408 of fig. 4-5) to the airflow in front of the fan 132 to reduce and/or otherwise eliminate the IFS.

In FIG. 6, an embodiment of the IFS controller 302 includes an example communication interface 610, an example ingress flow separation parameter determiner 620, an example ingress flow separation severity level parameter determiner 630, an example ingress flow separation detector 640, an example command generator 650, an example alert generator 660, and an example database 670. In FIG. 6, the database 670 includes example flight data 672, example sensor data 674, example IFS parameters 676, example IFS severity level parameters 678, an example IFS detection model 680, and example IFS control measures 682.

In the example of fig. 6, the IFS controller 302 includes a communication interface 610 to communicate with sensors (e.g., the first pressure sensor 304, the second pressure sensor 306, the third pressure sensor 308, the fourth pressure sensor 310, the first acceleration sensor 316, and/or the second acceleration sensor 318 of fig. 3-5), antennas (e.g., the first antenna 312 and/or the second antenna 314 of fig. 3-5), actuators (e.g., the first actuator 402 and/or the second actuator 404 of fig. 4-5), and/or an example computing system 612. For example, computing system 612 may correspond to one or more processor-based platforms associated with an aircraft, one or more processor-based platforms associated with an aircraft or turbofan engine manufacturer, and so forth. In some examples, the communication interface 610 obtains data or information from one or more of the sensors 304, 306, 308, 310, the antennas 312, 314, the actuators 402, 404, and/or the computing system 612 via a wired connection, a wireless connection, and/or the like, and/or combinations thereof.

In some examples, the communication interface 610 obtains flight data 672 from a computing system (e.g., computing system 612) on the aircraft. For example, communication interface 610 may obtain altitude data, speed data (e.g., airspeed data), etc., associated with turbofan engine 300, 400, 430 of fig. 3-5 and/or the aircraft to which turbofan engine 300, 400, 430 is more generally coupled. In such an example, the communication interface 610 may store the altitude data, velocity data, etc. as flight data 672 in the database 670.

In some examples, the communication interface 610 obtains the IFS command from the computing system 612. For example, communication interface 610 may obtain the IFS commands from an aircraft coupled to third turbofan engine 400 of fig. 4A, from a pilot of the aircraft that controls the aircraft from a cockpit of the aircraft, or the like. In such an example, the IFS command may increase the airflow contribution from the first section 406 or the second section 408 to the third section 410. In other examples, the IFS command may reduce the airflow contribution from the first section 406 or the second section 408 to the third section 410.

In some examples, the communication interface 610 transmits alerts, data, information, etc. to a computing system on the aircraft. For example, the communication interface 610 may transmit an alert to the aircraft control system to display the alert on a user interface of a display in the cockpit for presentation to the pilot. In such an example, the alert may include data, information, or the like as described below in connection with alert generator 660.

In some examples, the communication interface 610 obtains sensor data from one or more of the sensors 304, 306, 308, 310 of fig. 3-5. For example, the communication interface 610 may obtain pressure data (e.g., barometric pressure data) from the first pressure sensor 304 and the second pressure sensor 306 via the first antenna 312. In other examples, the communication interface 610 may obtain pressure data (e.g., barometric pressure data) from the third pressure sensor 308 and the fourth pressure sensor 310 via the second antenna 314.

In some examples, the communication interface 610 transmits commands, directions, instructions, or the like to one or more of the actuators 402, 404. For example, the communication interface 610 may communicate commands to the actuators 402, 404 via a wired connection to adjust from a first position to a second position. In other examples, the communication interface 610 may transmit a command to the first actuator 402 via the first antenna 312 to adjust from the first position to the second position. In still other examples, the communication interface 610 may transmit a command to the second actuator 404 via the second antenna 314 to adjust from the first position to the second position.

In fig. 6, the IFS controller 302 includes an IFS parameter determiner 620 to determine IFS parameters 676 based on sensor data associated with the turbofan engine and store the IFS parameters 676 in a database 670. The IFS parameters 676 may correspond to processed data values used by the IFS controller 302 to detect IFS events and/or determine the quantification or severity of IFS events. For example, the IFS parameter determiner 620 may determine one or more IFS parameters 676 associated with the turbofan engine 300, 400, 430 of FIGS. 3-5 including a first air pressure value at the first outer lip 208, a second air pressure value at the first inner lip 210, a third air pressure value at the second outer lip 212, a fourth air pressure value at the second inner lip 214, an air density, a Mach number, and/or a bearing load.

In some examples, the IFS parameter determiner 620 determines the first air pressure value based on the first air pressure data from the first pressure sensor 304 of fig. 3-5. The IFS parameter determiner 620 may determine a second air pressure value based on second air pressure data from the second pressure sensor 306 of fig. 3-5. The IFS parameter determiner 620 may determine a third air pressure value based on third air pressure data from the third pressure sensor 308 of fig. 3-5. The IFS parameter determiner 620 may determine a fourth air pressure value based on fourth air pressure data from the fourth pressure sensor 310 of fig. 3-5.

In some examples, the IFS parameter determiner 620 determines the air density based on the altitude data. For example, the IFS parameter determiner 620 may determine the air density of the air 142 of FIGS. 1-5 by mapping the altitude of the turbofan engine 300, 400, 430, the aircraft coupled to the turbofan engine 300, 400, 430, etc. stored in the flight data 672 to the air density. In such an example, the height-air density map may be stored in a look-up table (e.g., a look-up table in database 670).

In some examples, the IFS parameter determiner 620 determines the mach number based on the speed data. For example, the IFS parameter determiner 620 may obtain velocity data from the flight data 672 and determine mach number based on the obtained velocity data.

In some examples, the IFS parameter determiner 620 determines bearing loads, force values, vibrational responses, and/or the like, and/or combinations thereof, based on the acceleration data. For example, the communication interface 610 may obtain acceleration data from one or more of the acceleration sensors 316, 318 coupled to one or more of the bearings 317, 319 of the bearing section 320 of the engine 104 of fig. 3-5. The IFS parameter determiner 620 may determine a first bearing load, a first force value, a first vibrational response, etc. associated with the first bearing 317 based on first acceleration data obtained from the first acceleration sensor 316. The IFS parameter determiner 620 may determine a second bearing load, a second force value, a second vibrational response, etc. associated with the second bearing 319 based on second acceleration data obtained from the second acceleration sensor 318.

In FIG. 6, IFS controller 302 includes an IFS severity level parameter determiner 630 to determine a severity level parameter, such as IFS severity level parameter 678, based on IFS parameter 676. The IFS severity level parameter determiner 630 may store the IFS severity level parameters 678 in the database 670. The IFS severity level parameter 678 may correspond to a processed data value used by the IFS controller 302 to determine the quantification or severity of an IFS event. For example, the IFS severity level parameter determiner 630 may determine one or more IFS severity level parameters 678 associated with the turbofan engines 300, 400, 430 of fig. 3-5, including a first example severity level parameter 702 (fig. 7) based on airflow direction, a second example severity level parameter 704 (fig. 7) based on a pressure differential between the outer nacelle pressure and the inner nacelle pressure, and/or a third example severity level parameter 706 (fig. 7) based on engine vibration response.

Turning to FIG. 7, an example IFS severity level table 700 depicts an example determination of an IFS for use by the IFS controller 302 of FIGS. 3-6 to detect the turbofan engines 300, 400, 430 of FIGS. 3-5. IFS severity level table 700 represents example logic that IFS controller 302 may use to determine a first IFS severity level parameter 702, a second IFS severity level parameter 704, and a third IFS severity level parameter 706. Alternatively, the IFS controller 302 may determine fewer or more severity level parameters than depicted in FIG. 7.

In FIG. 7, a first IFS severity level parameter 702 indicates a flow direction (e.g., adverse flow direction, adverse airflow direction, etc.). For example, the IFS severity level parameter determiner 630 of fig. 6 may determine the flow direction based on a difference between Ps (e.g., a first pressure value from the first pressure sensor 304, a second pressure value from the third pressure sensor 308, etc.) and Pt (e.g., a pressure threshold), where Pt may be a predefined or predetermined pressure value. In such examples, Ps corresponds to a pressure value at the nacelle outer lip, such as a pressure value at the first outer lip 208 (e.g., a pressure value or measurement from the first pressure sensor 304), a pressure value at the second outer lip 212 (e.g., a pressure value or measurement from the third pressure sensor 308), and so forth. In response to determining that the difference satisfies a threshold, such as the difference being less than 0 (e.g., Ps < Pt) or a different value, the IFS severity level parameter determiner 630 may determine that the flow direction is substantially parallel (e.g., parallel in a range of-5 to 5 degrees, -2 to 2 degrees, etc.) to the nacelle outer lip.

In some examples, the IFS severity level parameter determiner 630 may determine that the turbofan engine 300, 400, 430 is experiencing a crosswind based on the direction of flow. For example, the IFS severity level parameter determiner 630 may detect crosswind based on a difference of approximately 0 (e.g., Ps ═ Pt, Ps approximately equal to Pt, etc.), which may indicate that the flow direction is perpendicular (e.g., 90 degrees with respect to the nacelle outer lip, perpendicular in a range of 85 to 95 degrees with respect to the nacelle outer lip, etc.) and/or otherwise incident on the nacelle outer lip. In such an example, the IFS severity level parameter determiner 630 may determine that the airflow is stagnant based on the difference being approximately 0, which may be indicative of a crosswind.

In some examples, the second IFS severity level parameter 704 is indicative of a cabin inlet pressure differential based on a difference between a first pressure value (Psouter) at an outer lip of the cabin and a second pressure value (psiinner) at an inner lip of the cabin. For example, the IFS severity level parameter determiner 630 may determine the second IFS severity level parameter 704 by determining a difference between a first pressure value at the first outer lip 208 of the first nacelle 134 and a second pressure value at the first inner lip 210 of the first nacelle 134. In such an example, the IFS severity level parameter determiner 630 may determine the second IFS severity level parameter 704 by normalizing the difference to the mach number (ν) and the air density (ρ) of the ambient air, as set forth in equation (1) below:

in some examples, the third IFS severity level parameter 706 indicates an engine vibration response based on acceleration data from a bearing accelerometer (e.g., the acceleration sensors 316, 318 of fig. 3-5). For example, the IFS severity level parameter determiner 630 may determine the third IFS severity level parameter 706 by generating an acoustic or vibrational response of a load at a bearing (e.g., the first bearing 317, the second bearing 319, etc.) included in the bearing section 320 of the engine 104 of fig. 3-5 based on acceleration data from one or more of the acceleration sensors 316, 318 coupled to the bearings 317, 319.

In fig. 7, the IFS severity level parameter determiner 630 may determine a first IFS severity level parameter 702, a second IFS severity level parameter 704, and a third IFS severity level parameter 706 based on example weight factors (e.g., scaling factors) 708, 710, 712. The weighting factors 708 include: a first example weight factor (wtFD)708, which corresponds to a flow direction weight factor; a second example weight factor (wtDP)710, which corresponds to a pressure differential weight factor; and a third example weighting factor (wtEVR) corresponding to an engine vibration response weighting factor. The IFS severity level parameter determiner 630 may use the weighting factors to increase or decrease the effect, impact and/or impact of the respective IFS severity level parameter 702, 704, 706 on the detection of the IFS event and/or the quantification of the severity of the detected IFS event.

In fig. 7, the IFS severity level parameter determiner 630 may determine the first IFS severity level parameter 702 based on a product and/or other mathematical operation of the output of the flow direction defining/determining logic and the first weight factor 708. In FIG. 7, the IFS severity level parameter determiner 630 may determine the second IFS severity level parameter 704 based on a product and/or other mathematical operation of the output of the cabin inlet pressure differential definition/determination logic and the second weighting factor 710. In FIG. 7, the IFS severity level parameter determiner 630 may determine the third IFS severity level parameter 706 based on the product of the output of the engine vibration response defining/determining logic and the third weighting factor 712 and/or other mathematical operation.

Returning to fig. 6, IFS controller 302 includes an IFS detector 640 to detect IFS conditions, events, etc. of turbofan engines 300, 400, 430 of fig. 3-5 based on IFS parameters 676. In some examples, the IFS detector 640 detects IFSs based on a comparison of the IFS detection model to one or more of the IFS detection models 680 stored in the database 670. For example, the IFS detector 640 may generate an IFS detection model based on a Probability Density Function (PDF). The IFS detector 640 may generate and/or otherwise determine a PDF based on at least one of the first IFS severity level parameter 702, the second IFS severity level parameter 704, or the third IFS severity level parameter 706. Alternatively, the IFS detection model may be a machine learning model, such as a neural network (e.g., convolutional neural network, deep neural network, etc.).

Returning to fig. 7, the IFS detector 640 may generate an IFS detection model including a PDF based on the first IFS severity level parameter 702, the second IFS severity level parameter 704, or the third IFS severity level parameter 706. The IFS detector 640 may compare the PDF to the first, second, and third example PDFs 714, 716, 718. PDFs 714, 716, 718 may be stored in database 670 as IFS detection model 680. In fig. 7, the first PDF 714 may correspond to the no IFS condition or the clean airflow condition at the inlet 144 of fig. 1-5.

In fig. 7, the second PDF 716 may correspond to a PDF generated based on adverse inlet flow direction and impact on the incoming inlet airflow to the fan 132. The IFS detector 640 may determine an adverse inlet flow direction based on the first IFS severity level parameter 702. The IFS detector 640 may determine an impact on the oncoming inlet airflow of the fan 132 based on the second IFS severity level parameter 704. In fig. 7, the adverse inlet flow direction and impact on the oncoming inlet airflow of the fan 132 may result in an average shift of the first PDF 714 to generate a second PDF 716.

In fig. 7, the third PDF 718 may correspond to a PDF generated based on adverse inlet flow direction, impact on the oncoming inlet airflow of the fan 132, and adverse engine vibration response. The IFS detector 640 may determine an adverse engine vibration response based on the third IFS severity level parameter 706. In fig. 7, adverse inlet flow direction, impact on the oncoming inlet airflow of the fan 132, and adverse engine vibration response may cause the mean deviation and standard deviation (STD DEV) of the first PDF 714 to vary, thereby generating a third PDF 718. In some examples, the IFS detector 640 detects an IFS at the inlet 144 of the turbofan engine 300, 400, 430 based on a comparison of the PDF based on the IFS severity level parameters 702, 704, 706 and the PDF 714, 716, 718 of fig. 7.

Returning to fig. 6, the IFS controller 302 includes a command generator 650 to generate commands, directions, instructions, etc. to control and/or otherwise invoke one or more of the actuators 402, 404 of fig. 4-5. In some examples, the command generator 650 invokes the communication interface 610 to transmit a command to the first antenna 312 to relay the command to the first actuator 402 to move the first actuator 402 from a first position to a second position, wherein the first position is different from the second position. In some such examples, the command generator 650 may invoke the first actuator 402 to facilitate a high airflow contribution from the first section 406 to the third section 410 and a low airflow contribution from the second section 408 to the third section 410.

In some examples, the command generator 650 invokes the communication interface 610 to transmit the command to the second actuator 404 via the wired connection (e.g., without transmitting the command to the second antenna 314). In such an example, the command generator 650 may invoke the second actuator 404 to adjust the position based on the command. In some such examples, the command generator 650 may invoke the second actuator 404 to facilitate a low airflow contribution from the first section 406 to the third section 410 and a high airflow contribution from the second section 408 to the third section 410. In other examples, the command generator 650 may invoke the second actuator 404 to facilitate an intermediate airflow contribution from the first section 406 to the third section 410 and an intermediate airflow contribution from the second section 408 to the third section 410.

In some examples, the command generator 650 determines one or more of the IFS control measures 682 based on the IFS severity level parameter 678. In fig. 6, IFS control action 682 is a command, instruction, sequence of commands or instructions, etc., and/or combinations thereof, that may be used by command generator 650 to reduce and/or otherwise eliminate IFS. For example, when the first IFS severity level parameter 702 indicates no IFS, the command generator 650 may determine not to deploy one of the IFS control measures 682.

In some examples, command generator 650 deploys a first one of IFS control measures 682 based on IFS severity level parameters 678. For example, when the first IFS severity level parameter 702 and/or the second IFS severity level parameter 704 indicate the presence of a substantially high IFS at the inlet 144, the command generator 650 may execute a first one of the IFS control measures 682 by controlling the actuators 402, 404 to facilitate a high core airflow contribution (e.g., a high contribution of airflow from the first section 406) and a low fan airflow contribution (e.g., a low contribution of airflow from the second section 408). In such an example, a first one of the IFS control measures 682 may include the command generator 650 transmitting a first command to the first actuator 402, transmitting a second command to the second actuator 404, transmitting a command sequence of the second command after the first command, and so forth.

In some examples, command generator 650 deploys a second one of IFS control measures 682 based on IFS severity level parameters 678. For example, when the first IFS severity level parameter 702 and/or the second IFS severity level parameter 704 indicate that a moderate quantification of IFS is present at the inlet 144, the command generator 650 may execute a second one of the IFS control measures 682 by controlling the actuators 402, 404 to facilitate a moderate core airflow contribution (e.g., a moderate contribution of airflow from the first section 406) and a moderate fan airflow contribution (e.g., a moderate contribution of airflow from the second section 408). In such an example, a second one of the IFS control measures 682 may include the command generator 650 transmitting a first command to the first actuator 402, transmitting a second command to the second actuator 404, transmitting a command sequence of the second command after the first command, and so forth.

In some examples, command generator 650 deploys a third one of IFS control measures 682 based on IFS severity level parameters 678. For example, when the first IFS severity level parameter 702 and/or the second IFS severity level parameter 704 indicate that a substantially low IFS is present at the inlet 144, the command generator 650 may execute a third of the IFS control measures 682 by controlling the actuators 402, 404 to promote a low core airflow contribution (e.g., a low contribution of airflow from the first section 406) and a high fan airflow contribution (e.g., a high contribution of airflow from the second section 408). In such an example, a third one of the IFS control measures 682 may include the command generator 650 transmitting a first command to the first actuator 402, transmitting a second command to the second actuator 404, transmitting a command sequence of the second command after the first command, and so forth.

In fig. 6, IFS controller 302 includes an alert generator 660 to generate alerts, warnings, etc. in response to detecting an IFS at inlet 144 of turbofan engine 300, 400, 430 of fig. 3-5. In some examples, alert generator 660 generates the alert by generating a log and/or report, transmitting the alert to be presented on one or more displays (e.g., one or more displays in an aircraft cockpit, or a smartphone, tablet or laptop display, etc.), transmitting the alert to a network (e.g., an aircraft control network), and/or the like, and/or combinations thereof.

In some examples, the alarm generator 660 stores information (e.g., generated alarms, logs, reports, etc.) in the database 670 and/or retrieves information from the database 670 to include in the alarm (e.g., IFS parameter 676, IFS severity level parameter 678, etc.). For example, alert generator 660 may store a report including maintenance alerts for fan blades 132 in database 670 based on the engine vibration response stored in IFS severity level parameter 678.

In some examples, the alert generator 660 records and/or otherwise stores flight data 672 (fig. 6) and/or sensor data 674 (fig. 6) associated with times before, during, and/or after actuation of the first actuator 402 and/or the second actuator 404 in the database 670. In such an example, the alert generator 660 can record which of the actuators 402, 404 are invoked in response to the IFS command, the location of one or more of the actuators 402, 404, and/or the like, and/or combinations thereof.

In FIG. 6, IFS controller 302 includes a database 670 to record and/or otherwise store data such as flight data 672, sensor data 674, IFS parameters 676, IFS severity level parameters 678, IFS detection model 680, and IFS control measures 682. The database 670 may be implemented by volatile memory (e.g., Synchronous Dynamic Random Access Memory (SDRAM), Dynamic Random Access Memory (DRAM), RAMBUS Dynamic Random Access Memory (RDRAM), etc.) and/or non-volatile memory (e.g., flash memory). The database 670 may additionally or alternatively be implemented by one or more Double Data Rate (DDR) memories (e.g., DDR2, DDR3, DDR4, mobile DDR (mddr), etc.). The database 670 may additionally or alternatively be implemented by one or more mass storage devices (e.g., hard disk drives, optical disk drives, digital versatile disk drives, solid state disk drives, etc.). Although database 670 is shown as a single database in the illustrated example, database 670 may be implemented by any number and/or type of databases. In addition, the data stored in database 670 may be in any data format, such as binary, comma separated, hexadecimal, JavaScript Object Notation (JSON), tab separated, Structured Query Language (SQL), XML, and the like.

Although an example implementation of the IFS controller 302 of fig. 3-5 is shown in fig. 6, one or more of the elements, processes and/or devices shown in fig. 6 may be combined, divided, rearranged, omitted, eliminated and/or implemented in any other way. Further, the example communication interface 610, the example IFS parameter determiner 620, the example IFS severity level parameter determiner 630, the example IFS detector 640, the example command generator 650, the example alert generator 660, the example database 670, and/or, more generally, the example IFS controller of fig. 3-5 may be implemented by hardware, software, firmware, and/or any combination of hardware, software, and/or firmware. Thus, for example, the example communication interface 610, the example IFS parameter determiner 620, the example IFS severity level parameter determiner 630, the example IFS detector 640, the example command generator 650, the example alert generator 660, any of the example database 670, and/or, more generally, the example IFS controller 302 may be implemented by one or more analog or digital circuits, logic circuits, programmable processors, programmable controllers, Graphics Processing Units (GPUs), Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Programmable Logic Devices (PLDs), and/or Field Programmable Logic Devices (FPLDs). When reading any device or system claims of this patent to encompass a purely software and/or firmware implementation, at least one of the example communication interface 610, the example IFS parameter determiner 620, the example IFS severity level parameter determiner 630, the example IFS detector 640, the example command generator 650, the example alert generator 660, and/or the example database 670 is hereby expressly defined to include a non-transitory computer readable storage device or storage disk, e.g., memory, Digital Versatile Disk (DVD), Compact Disk (CD), blu-ray disk, etc., containing the software and/or firmware. Still further, the example IFS controller 302 of fig. 3-5 may include one or more elements, processes and/or devices in addition to, or instead of, those shown in fig. 6, and/or may include more than one or all of the illustrated elements, processes and devices. As used herein, the phrase "communicate" includes variations thereof, encompasses direct communication and/or indirect communication via one or more intermediate components, and does not require direct physical (e.g., wired) communication and/or continuous communication, but additionally includes selective communication of periodic intervals, scheduled intervals, aperiodic intervals, and/or one-time events.

Flow diagrams representing example hardware logic, machine readable instructions, hardware implemented state machines, and/or any combination thereof for implementing the IFS controller 302 of fig. 3-6 are shown in fig. 8-12. The machine-readable instructions may be one or more executable programs or portions of executable programs for execution by a computer processor such as the processor 1312 shown in the example processor platform 1300 discussed below in connection with fig. 13. The program may be embodied in software stored on a non-transitory computer readable storage medium such as a CD-ROM, a floppy disk, a hard drive, a DVD, a blu-ray disk, or a memory associated with the processor 1312, but the entire program and/or parts thereof could alternatively be executed by a device other than the processor 1312 and/or embodied in firmware or dedicated hardware. Further, although the example program is described with reference to the flowcharts illustrated in FIGS. 8-12, many other methods of implementing the example IFS controller 302 may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Additionally or alternatively, any or all of the blocks may be implemented by one or more hardware circuits (e.g., discrete and/or integrated analog and/or digital circuits, FPGAs, ASICs, comparators, operational amplifiers (op-amps), logic circuitry, etc.) configured to perform the respective operations without executing software or firmware.

The machine-readable instructions described herein may be stored in one or more of a compressed format, an encrypted format, a fragmented format, a compiled format, an executable format, a packaged format, and the like. The machine-readable instructions described herein may be stored as data (e.g., portions of instructions, code, representations of code, etc.) that may be used to create, fabricate, and/or generate machine-executable instructions. For example, the machine-readable instructions may be segmented and stored on one or more storage devices and/or computing devices (e.g., servers). Machine-readable instructions may require one or more of installation, modification, adaptation, updating, merging, supplementing, constructing, decrypting, decompressing, unpacking, distributing, redistributing, compiling, etc., in order to be directly readable, interpretable, and/or executable by a computing device and/or other machine. For example, machine-readable instructions may be stored in multiple portions that are separately compressed, encrypted, and stored on separate computing devices, where the portions, when decrypted, decompressed, and combined, form a set of executable instructions that implement a program such as described herein.

In another example, machine-readable instructions may be stored in a state in which they can be read by a computer, but requires the addition of a library (e.g., a Dynamic Link Library (DLL)), a Software Development Kit (SDK), an Application Programming Interface (API), or the like, in order to execute the instructions on a particular computing device or other device. In another example, machine readable instructions may need to be structured (e.g., setup storage, data entry, network address records, etc.) before the machine readable instructions and/or corresponding program can be executed in whole or in part. Accordingly, the disclosed machine readable instructions and/or corresponding programs are intended to encompass such machine readable instructions and/or programs regardless of the particular format or state of the machine readable instructions and/or programs as they are stored or otherwise quiesced or transmitted.

The machine-readable instructions described herein may be represented by any past, present, or future instruction language, scripting language, programming language, or the like. For example, machine-readable instructions may be represented using any of the following languages: c, C + +, Java, C #, Perl, Python, JavaScript, HyperText markup language (HTML), Structured Query Language (SQL), Swift, and the like.

As described above, the example processes of fig. 8-12 may be implemented using executable instructions (e.g., computer and/or machine readable instructions) stored on a non-transitory computer and/or machine readable medium (e.g., a hard disk drive, a flash memory, a read-only memory, a compact disk, a digital versatile disk, a cache, a random-access memory, and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended periods of time, permanently, brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term non-transitory computer-readable medium is expressly defined to include any type of computer-readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media.

FIG. 8 is a flowchart representative of example machine readable instructions 800 that may be executed to implement the IFS controller 302 of FIGS. 3-6 to adjust the airflow contribution to the inlet 144 of the third turbofan engine 400 of FIGS. 4-5. The machine-readable instructions 800 of fig. 8 begin at block 802, where the IFS controller 302 determines an Inlet Flow Separation (IFS) parameter based on sensor data associated with the turbofan engine at block 802. For example, IFS parameter determiner 620 (FIG. 6) may determine one or more of IFS parameters 676 (FIG. 6) based on sensor data 674 (FIG. 6) associated with one or more of turbofan engines 300, 400, 430 (FIGS. 3-5). Example instructions that may be executed to implement block 802 are described below in conjunction with fig. 9.

At block 804, the IFS controller 302 detects an IFS based on the IFS parameters. For example, the IFS detector 640 (fig. 6) may detect the second airflow 504 of fig. 5, an IFS event represented by arrow 202 of fig. 2, and/or the like based on the IFS parameter 676, the IFS severity rating parameter 678 (fig. 6), and/or the like, and/or combinations thereof. Example instructions that may be executed to implement block 804 are described below in conjunction with FIG. 10.

At block 806, the IFS controller 302 determines whether an IFS is detected based on the IFS parameters. For example, the IFS detector 640 may not detect IFS based on the IFS parameter 676, the IFS severity level parameter 678, the like, and/or combinations thereof. In other examples, the IFS detector 640 may detect IFSs based on the IFS parameter 676, the IFS severity level parameter 678, the like, and/or combinations thereof.

If at block 806 the IFS controller 302 determines that an IFS has not been detected, control proceeds to block 816 to determine whether to continue monitoring the turbofan engine. If the IFS controller 302 determines that an IFS is detected at block 806, the IFS controller 302 identifies an IFS control action based on the IFS severity level parameter at block 808. For example, the IFS severity level parameter determiner 630 (FIG. 6) may determine one or more of the IFS severity level parameters 678 (FIG. 6). In such an example, the command generator 650 (fig. 6) may identify one or more of the IFS control measures 682 (fig. 6) based on the IFS severity level parameter 678. Example instructions that may be executed to implement block 808 are described below in conjunction with FIG. 11.

At block 810, the IFS controller 302 determines whether an IFS control measure has been identified. For example, in response to determining that the IFS severity level parameter 678 does not indicate an IFS, the command generator 650 may determine that no IFS control measures are to be deployed. In other examples, the command generator 650 may determine to invoke one or more of the actuators 402, 404 (fig. 4A and/or 4B) to adjust the IFS based on the IFS severity level parameter 678 that indicates a low, medium, or high IFS at the inlet portion 144.

If at block 810, the IFS controller 302 determines that there are no IFS control measures identified, control proceeds to block 816 to determine whether to continue monitoring the turbofan engine. If at block 810 IFS controller 302 determines that there is an identified IFS control measure, at block 812 IFS controller 302 controls an actuator to adjust the airflow contribution to inlet 144 of turbofan engine 300, 400, 430. For example, the command generator 650 may transmit commands to the actuators 402, 404 to adjust the position to adjust the airflow contribution from the first section 406 and/or the second section 408 to the third section 410 of fig. 4-5.

At block 814, the IFS controller 302 generates an alert. For example, the alert generator 660 (fig. 6) may generate an alert including at least one of flight data 672 (fig. 6), sensor data 674, one or more IFS parameters 676, one or more IFS severity level parameters 678, or one or more IFS control measures 682 deployed. In such examples, the alert generator 660 may transmit the alert to a display for presentation to a pilot in a cockpit of the aircraft, store the alert in a database 670 (fig. 6) for maintenance tasks or improvements to be performed on the turbofan engine 300, 400, 430, and/or the like, and/or combinations thereof.

At block 816, the IFS controller 302 determines whether to continue monitoring the turbofan engine. For example, communication interface 610 (fig. 6) may determine that turbofan engine 300, 400, 430 is not in flight (e.g., the aircraft has landed on the ground, taxied to a gate, stopped at a gate, etc.), and thus determine that turbofan engine 300, 400, 430 is no longer being monitored. In other examples, communication interface 610 may determine to continue monitoring turbofan engines 300, 400, 430 to determine whether the IFS has been reduced and/or otherwise eliminated in response to IFS control action 682 deployed at block 810.

If at block 816 the IFS controller 302 determines to continue monitoring the turbofan engine, control returns to block 802 to determine the IFS parameters based on sensor data associated with the turbofan engine. If at block 816 IFS controller 302 determines not to continue monitoring the turbofan engine, machine readable instructions 800 of FIG. 8 end.

FIG. 9 is a flowchart representative of example machine readable instructions 900 that may be executed to implement the IFS controller 302 of FIGS. 3-6 to determine the IFS parameter 676 of FIG. 6 based on the sensor data 674 of FIG. 6 associated with the second turbofan engine 300 of FIG. 3 and/or the third turbofan engine 400 of FIGS. 4-5. The machine-readable instructions 900 of fig. 9 may be executed to implement block 802 of fig. 8.

The machine-readable instructions 900 of fig. 9 begin at block 902, where at block 902 the IFS controller 302 obtains first barometric pressure data from a first barometric pressure sensor at an outer lip of a nacelle. For example, the communication interface 610 (fig. 6) may obtain first barometric pressure data from the first pressure sensor 304 and second barometric pressure data from the third pressure sensor 308.

At block 904, the IFS controller 302 determines a first air pressure value at the outer lip of the nacelle based on the first air pressure data. For example, the IFS parameter determiner 620 (fig. 6) may determine a first air pressure value at the first outer lip 208 based on the first air pressure data and a second air pressure value at the second outer lip 212 based on the second air pressure data.

At block 906, the IFS controller 302 obtains second air pressure data from a second air pressure sensor at the inboard lip of the nacelle. For example, the communication interface 610 may obtain third air pressure data from the second pressure sensor 306 and fourth air pressure data from the fourth pressure sensor 310.

At block 908, the IFS controller 302 determines a second air pressure value at the inner lip of the nacelle based on the second air pressure data. For example, the IFS parameter determiner 620 may determine a third air pressure value at the first inner lip 210 based on the third air pressure data and a fourth air pressure value at the second inner lip 214 based on the fourth air pressure data.

At block 910, the IFS controller 302 obtains altitude data and speed data from a database. For example, the IFS parameter determiner 620 may obtain altitude data and velocity data from flight data 672 (FIG. 6) stored in the database 670 (FIG. 6).

At block 912, the IFS controller 302 determines an air density based on the altitude data. For example, the IFS parameter determiner 620 may determine the air density based on the altitude data.

At block 914, the IFS controller 302 determines a mach number based on the speed data. For example, the IFS parameter determiner 620 may determine the mach number based on the speed data.

At block 916, the IFS controller 302 obtains acceleration data from the acceleration sensor. For example, the communication interface 610 may obtain acceleration data from one or more acceleration sensors 316, 318 coupled to one or more bearings 317, 319 of the bearing section 320 of the engine 104 of fig. 3-5.

At block 918, the IFS controller 302 determines a bearing load based on the acceleration data. For example, the IFS parameter determiner 620 may determine a first load on the first bearing 317, a second load on the second bearing 319, etc. of the engine 104 based on the acceleration data. In response to determining the bearing load based on the acceleration data at block 918, control returns to block 804 of the machine-readable instructions 800 of fig. 8 to detect the IFS based on the IFS parameters.

Fig. 10 is a flow diagram representing example machine readable instructions 1000 that the example machine readable instructions 1000 may be executed to implement the IFS controller 302 of fig. 3-6 to detect an IFS based on an IFS parameter. The machine-readable instructions 1000 of fig. 10 may be executed to implement block 804 of fig. 8.

The machine readable instructions 1000 of FIG. 10 begin at block 1002, where the IFS controller 302 determines an airflow direction based on a difference between an outer nacelle pressure and a pressure threshold at block 1002. For example, the IFS severity-level-parameter determiner 630 (fig. 6) may determine the first flow direction of the airflow at the first outer lip 208 based on a difference between the first pressure value from the first pressure sensor 304 and a pressure threshold. In such an example, the IFS severity level parameter determiner 630 may determine the second flow direction of the airflow at the second outer lip 212 based on a difference between the second pressure value from the third pressure sensor 308 and the pressure threshold.

At block 1004, IFS controller 302 determines a first IFS severity level parameter based on the airflow direction and a first weight factor. For example, the IFS severity level parameter determiner 630 may determine the first IFS severity level parameter 702 (fig. 7) associated with the first nacelle 134 based on the airflow direction at the first outer lip 208 and the first weight factor 708 (fig. 7). In such an example, the IFS severity level parameter determiner 630 may determine the first IFS severity level parameter 702 associated with the second nacelle 135 based on the airflow direction at the second outer lip 212 and the first weight factor 708.

At block 1006, the IFS controller 302 determines a pressure differential between the outer cabin pressure and the inner cabin pressure. For example, the IFS severity level parameter determiner 630 may determine a first pressure differential across the surface of the first nacelle 134 based on a first difference between a first pressure value from the first pressure sensor 304 and a second pressure value from the second pressure sensor 306. In such an example, the IFS severity level parameter determiner 630 may determine a second pressure differential across the surface of the second nacelle 135 based on a second difference between a third pressure value from the third pressure sensor 308 and a fourth pressure value from the fourth pressure sensor 310.

At block 1008, the IFS controller 302 determines a second IFS severity level parameter based on the pressure difference and a second weight factor. For example, the IFS severity level parameter determiner 630 may determine the second IFS severity level parameter 704 (fig. 7) associated with the first nacelle 134 based on the first pressure differential across the first outer lip 208 and the first inner lip 210 and the second weight factor 710 (fig. 7). In such an example, the IFS severity level parameter determiner 630 may determine the second IFS severity level parameter 704 associated with the second nacelle 135 based on a second pressure differential across the second outer lip 212 and the second inner lip 214 and the second weight factor 710.

At block 1010, the IFS controller 302 determines an engine vibration response based on the bearing load. For example, the IFS severity level parameter determiner 630 may determine the third IFS severity level parameter 706 (fig. 7) based on an engine vibration response generated based on acceleration data from one or more of the acceleration sensors 316, 318.

At block 1012, the IFS controller 302 determines a third IFS severity level parameter based on the engine vibration response and a third weight factor. For example, the IFS severity level parameter determiner 630 may determine the third IFS severity level parameter 706 associated with the engine 104 based on the engine vibration response associated with the engine 104 and the third weight factor 712 (FIG. 7).

At block 1014, the IFS controller 302 determines a probability density function based at least on the first through third severity level parameters. For example, the IFS detector 640 (fig. 6) may determine the probability density function based on one or more first IFS severity level parameters 702, one or more second IFS severity level parameters 704, one or more third IFS severity level parameters, and/or the like.

At block 1016, the IFS controller 302 compares the probability density function to a stored probability density function. For example, the IFS detector 640 may compare the probability density function to the first probability density function 714 (fig. 7), the second probability density function 716 (fig. 7), and/or the third probability density function 718 (fig. 7). In such an example, the first through third probability density functions 714, 716, 718 may be stored as an IFS detection model 680 in the database 670 (fig. 6).

At block 1018, the IFS controller 302 detects an IFS based on the comparison. For example, the IFS detector 640 may detect and/or otherwise determine the presence or occurrence of an IFS at the entry 144 of fig. 1-5 based on the comparison performed at block 1016. In response to detecting an IFS based on the comparison at block 1018, control returns to block 806 of the machine readable instructions 800 of fig. 8 to determine whether an IFS is detected.

FIG. 11 is a flowchart representative of example machine readable instructions 1100 that the example machine readable instructions 1100 may be executed to implement the IFS controller 302 of FIGS. 3-6 to identify an IFS control action 682 (FIG. 6) based on the IFS severity level parameter 678 (FIG. 6). The machine readable instructions 1100 of fig. 11 may be executed to implement block 808 of fig. 8.

The machine-readable instructions 1100 of fig. 11 begin at block 1102, where the IFS controller 302 determines whether the IFS severity level parameter indicates no IFS at block 1102. For example, the IFS detector 640 (FIG. 6) may determine that there is no IFS at the entry 144 based on the IFS severity level parameter 678. In other examples, the IFS detector 640 may determine that an IFS exists at the entry 144 based on the IFS severity level parameter 678.

If at block 1102, IFS controller 302 determines that the IFS severity level parameter indicates no IFS, then at block 1104 IFS controller 302 determines that no IFS control action is to be deployed. For example, command generator 650 (fig. 6) may determine not to deploy one or more of IFS control measures 682 stored in database 670 (fig. 6) based on IFS severity level parameters 678. In response to determining at block 1104 that there are no IFS control measures to deploy, control returns to block 810 of the machine readable instructions 800 of fig. 8 to determine whether an IFS control measure has been identified.

If at block 1102 the IFS controller 302 determines that the IFS severity level parameter does not indicate no IFS, control proceeds to block 1106 to determine whether the IFS severity level parameter indicates a high IFS. For example, the IFS detector 640 may determine that a substantially high IFS exists at the entry 144. In such an example, the IFS detector 640 may determine that the probability density function determined based on the IFS severity level parameters 702, 704, 706 of fig. 7 closely matches (e.g., within a predefined tolerance) and/or otherwise corresponds to the third probability density function 718 (fig. 7).

If at block 1106 IFS controller 302 determines that the IFS severity level parameter indicates a high IFS, then at block 1108 IFS controller 302 controls the actuator to facilitate a high core airflow contribution and a low fan airflow contribution. For example, the command generator 650 may map the detection of a high IFS to a first one of the IFS control measures 682 to achieve a high airflow contribution to be conveyed from the first section 406 to the third section 410 and a low airflow contribution to be conveyed from the second section 408 to the third section 410. In such an example, the command generator 650 may cause the actuators 402, 404 to increase airflow from the first section 406 and decrease airflow from the second section 408. In response to controlling the actuators to facilitate the high core airflow contribution and the low fan airflow contribution at block 1108, control returns to block 810 of the machine readable instructions 800 of FIG. 8 to determine whether an IFS control measure has been identified.

If at block 1106, the IFS controller 302 determines that the IFS severity level parameter does not indicate a high IFS, control proceeds to block 1110 to determine whether the IFS severity level parameter indicates a medium IFS. For example, the IFS detector 640 may determine that a medium level, number, etc. of IFSs are present at the entry 144. In such an example, the IFS detector 640 may determine that the probability density function determined based on the IFS severity level parameters 702, 704, 706 of fig. 7 closely matches (e.g., within a predefined tolerance) and/or otherwise corresponds to the second probability density function 716 (fig. 7).

If at block 1110 the IFS controller 302 determines that the IFS severity level parameter indicates a medium IFS, then at block 1112, the IFS controller 302 controls the actuator to facilitate a medium core airflow contribution and a medium fan airflow contribution. For example, the command generator 650 may map the detection of medium IFS to a second one of the IFS control actions 682 to achieve a medium airflow contribution to be introduced into the third section 410 from the first section 406 and a medium airflow contribution to be introduced into the third section 410 from the second section 408. In such an example, the command generator 650 may cause the actuators 402, 404 to adjust the airflow from the first section 406 (e.g., decrease from high to medium airflow, increase from low to medium airflow, etc.) and adjust the airflow from the second section 408 (e.g., increase from low to medium airflow, decrease from high to medium airflow, etc.). In response to controlling the actuator to facilitate the medium core airflow contribution and the medium fan airflow contribution at block 1112, control returns to block 810 of the machine readable instructions 800 of FIG. 8 to determine whether an IFS control measure has been identified.

If at block 1110 the IFS controller 302 determines that the IFS severity level parameter does not indicate a medium IFS, control proceeds to block 1114 to determine whether the IFS severity level parameter indicates a low IFS. For example, the IFS detector 640 may determine that a low IFS is present at the entry 144. In such an example, the IFS detector 640 may determine that the probability density functions determined based on the IFS severity level parameters 702, 704, 706 of fig. 7 do not closely match (e.g., are within a predefined tolerance) and/or otherwise correspond to any of the probability density functions 714, 716, 718 (fig. 7), or closely match the probability density functions associated with low IFSs.

If at block 1114 the IFS controller 302 determines that the IFS severity level parameter does not indicate a low IFS, control returns to block 810 of the machine readable instructions 800 of FIG. 8 to determine whether an IFS control measure has been identified. If at block 1114 the IFS controller 302 determines that the IFS severity level parameter indicates a low IFS, then at block 1116 the IFS controller 302 controls the actuator to facilitate a low core airflow contribution and a high fan airflow contribution. For example, the command generator 650 may map the detection of a low IFS to a third one of the IFS control measures 682 to result in a low airflow contribution to be introduced into the third section 410 from the first section 406 and a high airflow contribution to be introduced into the third section 410 from the second section 408. In such an example, the command generator 650 may cause the actuators 402, 404 to decrease the airflow from the first section 406 and increase the airflow from the second section 408. In response to controlling the actuators to facilitate the low core airflow contribution and the high fan airflow contribution at block 1116, control returns to block 810 of the machine readable instructions 800 of FIG. 8 to determine whether an IFS control measure has been identified.

FIG. 12 is a flowchart representative of example machine readable instructions 1200 that may be executed to implement the IFS controller 302 of FIGS. 3-6 to adjust airflow contribution to the inlet of the third turbofan engine 400 of FIG. 4A and/or the fourth turbofan engine 430 of FIG. 4B and/or FIG. 5. The machine-readable instructions 1200 of fig. 12 begin at block 1202 where the IFS controller 302 determines whether an Ingress Flow Separation (IFS) command has been obtained. For example, communication interface 610 (fig. 6) may obtain IFS commands from an aircraft coupled to third turbofan engine 400 of fig. 4A, from a pilot of the aircraft that controls the aircraft from a cockpit of the aircraft, or the like. In such an example, the IFS command may increase the airflow contribution from the first section 406 or the second section 408 to the third section 410. In other examples, the IFS command may reduce the airflow contribution from the first section 406 or the second section 408 to the third section 410.

If at block 1202 the IFS controller 302 determines that an IFS command has not been obtained, control waits for an IFS command at block 1202. If at block 1202 the IFS controller 302 determines that an IFS command has been obtained, control proceeds to block 1204 to identify an IFS control measure based on the IFS command. For example, command generator 650 (fig. 6) may map the command to one or more of IFS control measures 682 (fig. 6) to determine one or more actions to perform.

At block 1206, the IFS controller 302 determines whether the IFS control action includes increasing the airflow contribution behind the fan. For example, the command generator 650 may determine that the IFS control action 682 based on the IFS command includes controlling one or more of the actuators 402, 404 to increase the airflow contribution from the second section 408 to the third section 410.

If at block 1206 the IFS controller 302 determines that the IFS control action does not include increasing the contribution to airflow behind the fan, control proceeds to block 1210 to determine whether the IFS control action includes decreasing the contribution to airflow behind the fan. If at block 1206 IFS controller 302 determines that the IFS control action includes increasing the airflow contribution behind the fan, at block 1208 IFS controller 302 controls the actuator to increase the airflow contribution from behind the fan to the inlet of the turbofan engine. For example, the command generator 650 (fig. 6) may transmit a command to the first actuator 402 and/or the second actuator 404 to facilitate an increase in airflow from the second section 408 to the third section 410.

At block 1210, the IFS controller 302 determines whether the IFS control action includes reducing the airflow contribution behind the fan. For example, the command generator 650 may determine that the IFS control action 682 based on the IFS command includes controlling one or more of the actuators 402, 404 to reduce the airflow contribution from the second section 408 to the third section 410.

If at block 1210 the IFS controller 302 determines that the IFS control action does not include reducing the airflow contribution behind the fan, control proceeds to block 1214 to store data associated with the action in a database. If at block 1210 the IFS controller 302 determines that the IFS control action includes reducing the airflow contribution behind the fan, at block 1212 the IFS controller 302 controls the actuator to reduce the airflow contribution from behind the fan to the inlet of the turbofan engine. For example, the command generator 650 may transmit a command to the first actuator 402 and/or the second actuator 404 to facilitate a reduction in airflow from the second section 408 to the third section 410.

At block 1214, the IFS controller 302 stores data associated with the action in a database. For example, the alert generator 660 (fig. 6) may record and/or otherwise store flight data 672 (fig. 6) and/or sensor data 674 (fig. 6) associated with times before, during, and/or after actuation of the first actuator 402 and/or the second actuator 404 in the database 670 (fig. 6). In such an example, the alert generator 660 can record which of the actuators 402, 404 are invoked in response to the IFS command, the location of one or more of the actuators 402, 404, and/or the like, and/or combinations thereof.

At block 1216, the IFS controller 302 determines whether to continue monitoring the turbofan engine. If at block 1216 IFS controller 302 determines to continue monitoring the turbofan engine, control returns to block 1202 to determine if another IFS command has been obtained. If at block 1216 IFS controller 302 determines not to continue monitoring turbofan engines, machine readable instructions 1200 of FIG. 12 end.

FIG. 13 is a block diagram of an example processor platform 1300, the example processor platform 1300 configured to execute the instructions of FIGS. 8-12 to implement the IFS controller 302 of FIGS. 3-6. The processor platform 1300 may be, for example, an Electronic Control Unit (ECU), an Electronic Engine Control (EEC) unit, a Full Authority Digital Engine Control (FADEC) unit, a self-learning machine (e.g., a neural network), or any other type of computing device.

The processor platform 1300 of the illustrated example includes a processor 1312. The processor 1312 of the illustrated example is hardware. For example, the processor 1312 may be implemented by one or more integrated circuits, logic circuits, microprocessors, GPUs, DSPs, or controllers from any desired family or manufacturer. The hardware processor may be a semiconductor-based (e.g., silicon-based) device. In this example, the processor 1312 implements the IFS parameter determiner 620, the IFS severity level parameter determiner 630, the IFS detector 640, the command generator 650 and the alarm generator 660 of fig. 6. In FIG. 13, the IFS parameter determiner 620 is depicted as "IFS PARAM DETER", the IFS severity level parameter determiner 630 is depicted as "IFS SL PARAM DETER", and the command generator 650 is depicted as "CMD generator" 650.

The processor 1312 of the illustrated example includes a local memory 1313 (e.g., a cache). The processor 1312 of the illustrated example communicates with main memory including a volatile memory 1314 and a non-volatile memory 1316 via a bus 1318. The volatile memory 1314 may be implemented by Synchronous Dynamic Random Access Memory (SDRAM), Dynamic Random Access Memory (DRAM),dynamic random access memoryAnd/or any other type of random access memory device. The non-volatile memory 1316 may be implemented by flash memory and/or any other desired type of memory device. Access to the main memory 1314, 1316 is controlled by a memory controller.

The processor platform 1300 of the illustrated example also includes an interface circuit 1320. The interface circuit 1320 may be implemented by any type of interface standard (e.g., ethernet interface, Universal Serial Bus (USB),an interface, a Near Field Communication (NFC) interface and/or a PCI express interface). In this example, interface circuit 1320 implements communication interface 610 of fig. 6.

In the illustrated example, one or more input devices 1322 are connected to the interface circuit 1320. Input device(s) 1322 allow a user to enter data and/or commands into the processor 1312. The input device 1322 may be implemented by, for example, an audio sensor, a microphone, a camera (still or video), a keyboard, a button, a mouse, a touch screen, a touch pad, a trackball, an isopoint device, and/or a voice recognition system.

One or more output devices 1324 are also connected to the interface circuit 1320 of the illustrated example. The output devices 1324 may be implemented, for example, by display devices (e.g., Light Emitting Diodes (LEDs), Organic Light Emitting Diodes (OLEDs), Liquid Crystal Displays (LCDs), Cathode Ray Tube (CRT) displays, in-place switching (IPS) displays, touch screens, etc.), tactile output devices, printers, and/or speakers. Thus, the interface circuit 1320 of the illustrated example generally includes a graphics driver card, a graphics driver chip, and/or a graphics driver processor.

The interface circuit 1320 of the illustrated example also includes a communication device (e.g., a transmitter, receiver, transceiver, modem, residential gateway, wireless access point, and/or network interface) to facilitate exchange of data with external machines (e.g., any kind of computing device) via the network 1326. The communication may be via, for example, an ethernet connection, a Digital Subscriber Line (DSL) connection, a telephone line connection, a coaxial cable system, a satellite system, a field line wireless system, a cellular telephone system, etc.

The processor platform 1300 of the illustrated example also includes one or more mass storage devices 1328 for storing software and/or data. Examples of such mass storage devices 1328 include floppy disk drives, hard disk drives, optical disk drives, blu-ray disk drives, Redundant Array of Independent Disks (RAID) systems, and Digital Versatile Disk (DVD) drives. In this example, one or more mass storage devices 1328 implement the database 670, flight data 672, sensor data 674, IFS parameters 676, IFS severity level parameters 678, IFS detection model 680, and IFS control measures 682 of FIG. 6. In FIG. 13, IFS severity level parameter 678 is depicted as "IFS SL PARAM", IFS detection model 680 is depicted as "DETECT model", and IFS control action 682 is depicted as "CNTL action".

The machine-executable instructions 1332 of fig. 8-12 may be stored in the mass storage device 1328, in the volatile memory 1314, in the non-volatile memory 1316, and/or on a removable non-transitory computer-readable storage medium (e.g., a CD or DVD).

In light of the foregoing, it will be appreciated that example methods, apparatus, and articles of manufacture to detect and/or control airflow separation of an engine have been disclosed. Example methods, apparatus and articles of manufacture determine IFS parameters based on flight data, sensor data, and/or the like, and may determine IFS severity level parameters based on the IFS parameters. Example methods, apparatus and articles of manufacture may detect IFS and/or quantification and/or severity of IFS based on IFS parameters, IFS severity level parameters, and/or the like. Example methods, apparatus, and articles may control one or more actuators to adjust airflow emissions to an inlet section of an engine based on IFS detection. Advantageously, the example methods, apparatus and articles may improve the reliability and/or operating life of engine components and/or more generally engines by detecting IFSs and reducing and/or otherwise eliminating IFSs in response to the detection.

The disclosed methods, apparatus and articles of manufacture improve the efficiency of using computing devices (such as ECUs, FADEC, etc.) by preprocessing data (such as IFS parameters, IFS severity level parameters, etc.) prior to detecting IFS. Advantageously, by preprocessing data, the disclosed methods, apparatus and articles of manufacture may use reduced computational resources to detect IFSs as compared to using unprocessed data to detect IFSs. Accordingly, the disclosed methods, apparatus, and articles of manufacture are directed to one or more improvements in computer functionality.

Further aspects of the invention are provided by the subject matter of the following clauses:

1. an apparatus comprising hardware and memory, the memory including instructions that, when executed, cause the hardware to at least: determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of the turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter being based on a difference between the first pressure value and the second pressure value; and adjusting a contribution of airflow from behind a fan of the turbofan engine based on the severity-level parameter.

2. The apparatus of any preceding item, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the severity level parameter is a first severity level parameter, and the hardware: determining an airflow direction at the outer lip based on a difference between the first pressure value and a threshold value; determining a second severity level parameter based on the difference and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

3. The apparatus of any preceding item, wherein the hardware: determining a first probability density function based on the first severity level parameter and the second severity level parameter; comparing the first probability density function to a second probability density function stored in a database; and detecting inlet flow separation at the inlet of the turbofan engine based on the comparison.

4. The apparatus of any preceding item, wherein a first pressure sensor is coupled to an outer lip of the nacelle, a second pressure sensor is coupled to an inner lip of the nacelle, the severity-level parameter corresponds to a nacelle inlet pressure differential, and the hardware: determining a cabin inlet pressure difference based on a difference between the first pressure value and the second pressure value; determining a severity level parameter based on the cabin inlet pressure differential and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the severity level parameter.

5. The apparatus of any preceding item, wherein the severity level parameter is a first severity level parameter, and the hardware: obtaining acceleration data from an accelerometer coupled to a bearing of a turbofan engine; determining a vibratory response of the turbofan engine based on the acceleration data; determining a second severity level parameter based on the vibration response and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

6. The apparatus of any preceding item, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the second pressure sensor is coupled to an inner lip of the nacelle, and the hardware: obtaining altitude data and speed data from an aircraft coupled to a turbofan engine; determining an air density based on the altitude data; determining a mach number based on the speed data; and determining an inlet flow separation parameter based on at least one of the first pressure value, the second pressure value, the air density, or the mach number.

7. The apparatus of any preceding item, wherein the hardware adjusts the contribution of airflow from behind the fan by controlling an actuator included in the nacelle based on the severity-level parameter, the actuator moving from a first position to a second position to adjust the contribution of airflow from behind the fan to in front of the fan.

8. An apparatus, comprising: an inlet flow separation parameter determiner that determines an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of the turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; an inlet flow separation severity level parameter determiner that determines a severity level parameter based on the inlet flow separation parameter, the severity level parameter based on a difference between the first pressure value and the second pressure value; and a command generator that adjusts a contribution of airflow from behind a fan of the turbofan engine based on the severity level parameter.

9. The apparatus of any preceding item, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the severity level parameter is a first severity level parameter, the inlet flow separation severity level parameter determiner: determining an airflow direction at the outer lip based on a difference between the first pressure value and a threshold value; and determining a second severity level parameter based on the difference and the weight value; and further comprising an inlet flow separation detector that detects inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

10. The apparatus of any preceding item, wherein the inlet flow separation detector: determining a first probability density function based on the first severity level parameter and the second severity level parameter; comparing the first probability density function to a second probability density function stored in a database; and detecting inlet flow separation at the inlet of the turbofan engine based on the comparison.

11. The apparatus of any preceding clause, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the second pressure sensor is coupled to an inner lip of the nacelle, the severity level parameter corresponds to a nacelle inlet pressure differential, the inlet flow separation severity level parameter determiner: determining a cabin inlet pressure difference based on a difference between the first pressure value and the second pressure value; determining a severity level parameter based on the cabin inlet pressure differential and the weight value; and further comprising an inlet flow separation detector that detects inlet flow separation at the inlet of the turbofan engine based on the severity level parameter.

12. The apparatus of any preceding item, wherein the severity level parameter is a first severity level parameter, further comprising a collection engine that obtains acceleration data from an accelerometer coupled to a bearing of the turbofan engine, an inlet flow separation severity level parameter determiner: determining a vibratory response of the turbofan engine based on the acceleration data; determining a second severity level parameter based on the vibration response and the weight value; and further comprising an inlet flow separation detector that detects inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

13. The apparatus of any preceding item, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the second pressure sensor is coupled to an inner lip of the nacelle, and further comprising a collection engine that obtains altitude data and speed data from an aircraft coupled to the turbofan engine, and the inlet flow separation parameter determiner: determining an air density based on the altitude data; determining a mach number based on the speed data; and determining an inlet flow separation parameter based on at least one of the first pressure value, the second pressure value, the air density, or the mach number.

14. The apparatus of any preceding item, wherein the command generator adjusts the contribution of airflow from behind the fan by controlling an actuator included in the nacelle based on the severity-level parameter, the command generator invoking the actuator to move from a first position to a second position to adjust the contribution of airflow from behind the fan to in front of the fan.

15. A non-transitory computer-readable storage medium comprising instructions that, when executed, cause at least one processor to at least: determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of the turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter being based on a difference between the first pressure value and the second pressure value; and adjusting a contribution of airflow from behind a fan of the turbofan engine based on the severity-level parameter.

16. The non-transitory computer-readable storage medium of any preceding item, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the severity-level parameter is a first severity-level parameter, and the instructions, when executed, cause the at least one processor to: determining an airflow direction at the outer lip based on a difference between the first pressure value and a threshold value; determining a second severity level parameter based on the difference and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

17. The non-transitory computer-readable storage medium of any preceding item, wherein the instructions, when executed, cause at least one processor to: determining a first probability density function based on the first severity level parameter and the second severity level parameter; comparing the first probability density function to a second probability density function stored in a database; and detecting inlet flow separation at the inlet of the turbofan engine based on the comparison.

18. The non-transitory computer readable storage medium of any preceding clause, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the second pressure sensor is coupled to an inner lip of the nacelle, the severity-level parameter corresponds to a nacelle-inlet pressure differential, and the instructions, when executed, cause the at least one processor to: determining a cabin inlet pressure difference based on a difference between the first pressure value and the second pressure value; determining a severity level parameter based on the cabin inlet pressure differential and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the severity level parameter.

19. The non-transitory computer-readable storage medium of any preceding item, wherein the severity level parameter is a first severity level parameter, and the instructions, when executed, cause the at least one processor to: obtaining acceleration data from an accelerometer coupled to a bearing of a turbofan engine; determining a vibratory response of the turbofan engine based on the acceleration data; determining a second severity level parameter based on the vibration response and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

20. The non-transitory computer readable storage medium of any preceding item, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the second pressure sensor is coupled to an inner lip of the nacelle, and the instructions, when executed, cause the at least one processor to: obtaining altitude data and speed data from an aircraft coupled to a turbofan engine; determining an air density based on the altitude data; determining a mach number based on the speed data; and determining an inlet flow separation parameter based on at least one of the first pressure value, the second pressure value, the air density, or the mach number.

21. The non-transitory computer readable storage medium of any preceding item, wherein the instructions, when executed, cause the at least one processor to adjust the contribution of airflow from behind the fan by controlling an actuator included in the nacelle based on the severity-level parameter, the actuator moving from a first position to a second position to adjust the contribution of airflow from behind the fan to in front of the fan.

22. A method, comprising: determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of a turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter being based on a difference between the first pressure value and the second pressure value; and adjusting a contribution of airflow from behind a fan of the turbofan engine based on the severity-level parameter.

23. The method of any preceding item, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the severity-level parameter is a first severity-level parameter, and further comprising: determining an airflow direction at the outer lip based on a difference between the first pressure value and a threshold value; determining a second severity level parameter based on the difference and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

24. The method of any preceding clause, further comprising: determining a first probability density function based on the first severity level parameter and the second severity level parameter; comparing the first probability density function to a second probability density function stored in a database; and detecting inlet flow separation at the inlet of the turbofan engine based on the comparison.

25. The method of any preceding claim, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the second pressure sensor is coupled to an inner lip of the nacelle, the severity-level parameter corresponds to a nacelle inlet pressure differential, and further comprising: determining a cabin inlet pressure difference based on a difference between the first pressure value and the second pressure value; determining a severity level parameter based on the cabin inlet pressure differential and the weight value; and determining an inlet flow separation at the inlet of the turbofan engine based on the severity level parameter.

26. The method of any preceding item, wherein the severity level parameter is a first severity level parameter, and further comprising: obtaining acceleration data from an accelerometer coupled to a bearing of a turbofan engine; determining a vibratory response of the turbofan engine based on the acceleration data; determining a second severity level parameter based on the vibration response and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

27. The method of any preceding claim, wherein the first pressure sensor is coupled to an outer lip of the nacelle and the second pressure sensor is coupled to an inner lip of the nacelle, and further comprising: obtaining altitude data and speed data from an aircraft coupled to a turbofan engine; determining an air density based on the altitude data; determining a mach number based on the speed data; and determining an inlet flow separation parameter based on at least one of the first pressure value, the second pressure value, the air density, or the mach number.

28. The method of any preceding item, wherein adjusting the contribution of airflow from behind the fan comprises controlling an actuator included in the nacelle based on the severity-level parameter, the actuator moving from a first position to a second position to adjust the contribution of airflow from behind the fan to in front of the fan.

29. An apparatus comprising hardware and memory, the memory including instructions that, when executed, cause the hardware to at least: determining an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of the turbofan engine and a second pressure value from a second pressure sensor included in the nacelle; and determining a severity level parameter based on the inlet flow separation parameter, the severity level parameter being based on a difference between the first pressure value and the second pressure value.

30. The apparatus of any preceding item, wherein the hardware adjusts the contribution of airflow from behind a fan of the turbofan engine based on the severity-level parameter.

31. The apparatus of any preceding clause, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the severity level parameter is a first severity level parameter, and the hardware: determining an airflow direction at the outer lip based on a difference between the first pressure value and a threshold value; determining a second severity level parameter based on the difference and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

32. The apparatus of any preceding item, wherein the hardware: determining a first probability density function based on the first severity level parameter and the second severity level parameter; comparing the first probability density function to a second probability density function stored in a database; and detecting inlet flow separation at the inlet of the turbofan engine based on the comparison.

33. The apparatus of any preceding item, wherein a first pressure sensor is coupled to an outer lip of the nacelle, a second pressure sensor is coupled to an inner lip of the nacelle, the severity-level parameter corresponds to a nacelle inlet pressure differential, and the hardware: determining a cabin inlet pressure difference based on a difference between the first pressure value and the second pressure value; determining a severity level parameter based on the cabin inlet pressure differential and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the severity level parameter.

34. The apparatus of any preceding item, wherein the severity level parameter is a first severity level parameter, and the hardware: obtaining acceleration data from an accelerometer coupled to a bearing of a turbofan engine; determining a vibratory response of the turbofan engine based on the acceleration data; determining a second severity level parameter based on the vibration response and the weight value; and detecting inlet flow separation at the inlet of the turbofan engine based on the first severity level parameter and the second severity level parameter.

35. The apparatus of any preceding item, wherein the first pressure sensor is coupled to an outer lip of the nacelle, the second pressure sensor is coupled to an inner lip of the nacelle, and the hardware: obtaining altitude data and speed data from an aircraft coupled to a turbofan engine; determining an air density based on the altitude data; determining a mach number based on the speed data; and determining an inlet flow separation parameter based on at least one of the first pressure value, the second pressure value, the air density, or the mach number.

36. The apparatus of any preceding item, wherein the hardware adjusts the contribution of airflow from behind the fan by controlling an actuator included in the nacelle based on the severity-level parameter, the actuator moving from a first position to a second position to adjust the contribution of airflow from behind the fan to in front of the fan.

Although certain example methods, apparatus and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus, and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.

The following claims are hereby incorporated by reference into this detailed description, with each claim standing on its own as a separate embodiment of the disclosure.