阅读说明：本技术 用于燃气涡轮发动机的油冷却系统 (Oil cooling system for gas turbine engine ) 是由 J.D.兰博 A.马丁 C.W.斯托弗 J.M.沃尔夫 M.E.H.森诺恩 于 2017-07-18 设计创作，主要内容包括：一种用于包括外发动机壳的燃气涡轮发动机的热交换器组件。该热交换器组件包括至少一个冷却通道,该至少一个冷却通道构造成接收待冷却的流体流。至少一个第一制冷剂流管道构造成接收第一制冷剂流,其中该至少一个冷却通道配置在第一进口和第一出口之间。热交换器组件还包括至少一个第二制冷剂流管道,该至少一个第二制冷剂流管道构造成接收第二制冷剂流,其中该至少一个冷却通道配置在第二进口和第二出口之间。(A heat exchanger assembly for a gas turbine engine includes an outer engine casing. The heat exchanger assembly includes at least one cooling channel configured to receive a flow of fluid to be cooled. At least one first refrigerant flow conduit is configured to receive a first refrigerant flow, wherein the at least one cooling passage is disposed between the first inlet and the first outlet. The heat exchanger assembly also includes at least one second refrigerant flow conduit configured to receive a second refrigerant flow, wherein the at least one cooling passage is disposed between the second inlet and the second outlet.)

1. A heat exchanger assembly for a gas turbine engine including an outer engine casing, the heat exchanger assembly comprising:

at least one cooling channel adjacent to the outer engine casing, the at least one cooling channel configured to receive a flow of fluid to be cooled;

at least one first refrigerant flow conduit configured to receive a first refrigerant flow from a first inlet to a first outlet, wherein the at least one cooling passage is disposed between the first inlet and the first outlet; and

at least one second refrigerant flow conduit configured to receive a second refrigerant flow from a second inlet to a second outlet, wherein the at least one cooling passage is disposed between the second inlet and the second outlet.

2. The heat exchanger assembly of claim 1, further comprising at least one ejector disposed downstream of the at least one cooling passage, the at least one ejector configured to selectively receive a flow of high pressure fluid and draw the second flow of refrigerant through the at least one second refrigerant flow conduit.

3. The heat exchanger assembly of claim 1, further comprising a filter positioned between the at least one cooling passage and the at least one ejector, the filter configured to remove particulates entrained within the second refrigerant flow.

4. The heat exchanger assembly of claim 1, wherein the gas turbine engine further comprises a fan case assembly at least partially surrounding the outer engine casing defining a bypass duct configured to receive a fan jet flow, the second refrigerant flow comprising at least a portion of the fan jet flow, the second outlet of the at least one second refrigerant flow duct discharging at least one of the second refrigerant flow and the high pressure fluid flow back into the bypass duct.

5. The heat exchanger assembly of claim 1, wherein the second outlet of the at least one second refrigerant flow conduit discharges at least one of the second refrigerant flow and the high pressure fluid flow into a thermal management system of the gas turbine engine.

6. The heat exchanger assembly of claim 1, wherein the at least one first refrigerant flow conduit is coupled in flow communication with a Variable Bleed Valve (VBV) conduit and the first refrigerant flow comprises a VBV discharge flow received from the VBV conduit, the first outlet being defined within the outer engine shell.

7. The heat exchanger assembly of claim 1, wherein the at least one cooling passage is recessed within the outer engine shell.

8. The heat exchanger assembly of claim 1, further comprising at least one turning vane disposed at the first inlet, the at least one turning vane configured to direct the first refrigerant flow into the at least one first refrigerant flow conduit.

9. A gas turbine engine, comprising:

an engine assembly including an outer engine casing;

a fan case assembly at least partially surrounding the outer engine case, thereby defining a bypass duct configured to receive a fan jet flow;

an outlet guide vane assembly including a plurality of outlet guide vane segments coupled between the engine assembly and the fan case assembly, the plurality of outlet guide vane segments being circumferentially spaced around the engine assembly; and

a heat exchanger assembly adjacent the outer engine shell, the heat exchanger assembly comprising:

at least one cooling channel recessed within the outer engine casing, the at least one cooling channel configured to receive a flow of fluid to be cooled;

at least one first refrigerant flow conduit configured to receive a first refrigerant flow from a first inlet to a first outlet during low engine speeds, wherein the at least one cooling passage is configured between the first inlet and the first outlet; and

at least one second refrigerant flow conduit configured to receive a second refrigerant flow from a second inlet to a second outlet during high engine speeds, wherein the at least one cooling passage is disposed between the second inlet and the second outlet.

10. The gas turbine engine of claim 9, wherein the heat exchanger assembly is a first heat exchanger assembly, the gas turbine engine further comprising: at least one second heat exchanger assembly disposed adjacent the bypass duct, the second heat exchanger assembly including at least one second cooling passage configured to receive a flow of fluid to be cooled; and

a manifold system including at least one conduit configured to couple the first heat exchanger assembly and the at least one second heat exchanger assembly in flow communication, the manifold system further including an inlet connection configured to receive a flow of fluid to be cooled from the engine assembly and an outlet connection configured to direct the cooled fluid to the engine assembly.

11. The gas turbine engine of claim 10, wherein the header system further comprises a valve configured to selectively bypass the at least one second heat exchanger assembly having a fluid flow to be cooled.

12. The gas turbine engine of claim 10, wherein the at least one second heat exchanger assembly includes an outlet guide vane heat exchanger assembly adjacent to an outlet guide vane segment of the plurality of outlet guide vane segments and an outer fan case heat exchanger assembly adjacent to the fan case assembly.

13. The gas turbine engine of claim 9, further comprising at least one ejector disposed downstream of the at least one cooling passage, the at least one ejector configured to selectively receive a high pressure fluid flow and draw the second refrigerant flow through the at least one second refrigerant flow.

14. The gas turbine engine of claim 9, wherein the second refrigerant flow comprises at least a portion of the fan jet flow, the second outlet of the at least one second refrigerant flow conduit discharging at least one of the second refrigerant flow and the high pressure fluid flow into the bypass conduit.

15. The gas turbine engine of claim 9, further comprising at least one turning vane disposed at the first inlet, the at least one turning vane configured to direct the first refrigerant flow into the at least one first refrigerant flow conduit.

16. A heat exchanger assembly for a gas turbine engine, the gas turbine engine including a fan case and an outer engine case defining a bypass duct configured to receive a fan jet flow, the heat exchanger assembly comprising:

at least one cooling channel adjacent to the bypass duct, the at least one cooling channel configured to receive a fluid flow to be cooled;

at least one refrigerant flow conduit configured to receive a flow of refrigerant from at least one inlet to at least one outlet defined within the bypass conduit, wherein the at least one cooling passage is configured between the at least one inlet and the at least one outlet; and

at least one ejector disposed downstream of the at least one cooling passage, the at least one ejector configured to selectively receive a flow of high pressure fluid and draw the flow of refrigerant through the at least one refrigerant flow conduit.

17. The heat exchanger assembly of claim 16, wherein the at least one injector includes two inlet passages, a first inlet passage coupled in flow communication with a Variable Bleed Valve (VBV) conduit and the high pressure fluid flow includes a VBV exhaust flow, and a second inlet passage coupled in flow communication with a bleed air conduit and the high pressure fluid flow includes a bleed exhaust flow, wherein the first inlet passage is open during low engine speeds and the second inlet passage is open during high engine speeds.

18. The heat exchanger assembly of claim 16, wherein the at least one inlet comprises at least one inlet cover spaced a predetermined distance from the outer engine shell defining at least one opening therein, wherein the refrigerant flow is further configured to provide fan jet boundary suction at the at least one opening for the fan jet flow.

19. The heat exchanger assembly of claim 16, further comprising a filter between the at least one cooling passage and the at least one ejector, the filter configured to remove particulates entrained within the second refrigerant flow.

20. The heat exchanger assembly of claim 16, wherein the at least one outlet of the at least one refrigerant flow conduit discharges at least one of the refrigerant flow and the high pressure fluid flow into a thermal management system of the gas turbine engine.

Technical Field

The field of the present disclosure relates generally to gas turbine engines and, more particularly, to oil cooling systems for gas turbine engines.

Background

Gas turbine engines, such as turbofan engines, typically include an oil system that dispenses engine oil for cooling and lubricating components within the gas turbine engine. As turbofan engines become larger, faster, and more powered, more heat within the engine oil needs to be dissipated, thus increasing the cooling requirements of the oil cooling system that helps extract heat from the engine oil.

At least some known oil cooling systems include a heat exchanger positioned within a bypass duct that draws fan jet air therethrough for turbofan propulsion. The oil is directed through a heat exchanger where fan jet air is used as the refrigerant and heat is transferred from the oil to the fan jet air. However, some heat exchangers are known to create drag within the fan jet air, which reduces turbofan engine efficiency. Furthermore, during low speed conditions of the turbofan engine (such as ground operating conditions), the fan jet air drawn through the bypass duct is low or non-existent, thereby reducing the efficiency of the heat exchanger. Furthermore, dedicated oil cooling systems for low engine speed conditions increase the weight of the turbofan engine, which also reduces overall efficiency.

Disclosure of Invention

In one embodiment, a heat exchanger assembly for a gas turbine engine is provided. The gas turbine engine includes an outer engine casing. The heat exchanger assembly includes at least one cooling passage adjacent the outer engine shell configured to receive a flow of fluid to be cooled. The at least one first refrigerant flow conduit is configured to receive a first refrigerant flow from the first inlet to the first outlet, wherein the at least one cooling passage is disposed between the first inlet and the first outlet. The heat exchanger assembly also includes at least one second refrigerant flow conduit configured to receive a second refrigerant flow from the second inlet to the second outlet, wherein the at least one cooling passage is disposed between the second inlet and the second outlet.

In another embodiment, a gas turbine engine is provided. The gas turbine engine includes an engine assembly including an outer engine casing. The fan case assembly at least partially surrounds the outer engine case, thereby defining a bypass duct configured to receive a fan jet flow (fan flow). The outlet guide vane assembly includes a plurality of outlet guide vane segments coupled between the engine assembly and the fan case assembly, the plurality of outlet guide vane segments being circumferentially spaced around the engine assembly. The gas turbine engine also includes a heat exchanger assembly adjacent the outer engine casing. The heat exchanger assembly includes at least one cooling passage recessed within the outer engine casing, the at least one cooling passage configured to receive a flow of fluid to be cooled. The at least one first refrigerant flow conduit is configured to receive a first refrigerant flow from the first inlet to the first outlet during low engine speeds, wherein the at least one cooling passage is disposed between the first inlet and the first outlet. The heat exchanger assembly also includes at least one second refrigerant flow conduit configured to receive a second refrigerant flow from the second inlet to the second outlet during high engine speeds, wherein the at least one cooling passage is disposed between the second inlet and the second outlet.

In yet another embodiment, a heat exchanger assembly for a gas turbine engine is provided. The gas turbine engine includes a fan case and an outer engine case defining a bypass duct configured to receive a fan jet flow. The heat exchanger assembly includes at least one cooling channel adjacent the bypass conduit, the at least one cooling channel configured to receive a flow of fluid to be cooled. At least one refrigerant flow conduit is configured to receive a flow of refrigerant from at least one inlet to at least one outlet defined within the bypass conduit, wherein the at least one cooling passage is disposed between the at least one inlet and the at least one outlet. The heat exchanger assembly also includes at least one ejector disposed downstream of the at least one cooling passage, the at least one ejector configured to selectively receive the flow of high pressure fluid and draw the flow of refrigerant through the at least one refrigerant flow conduit.

Drawings

These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

FIG. 1 is a schematic, cross-sectional illustration of an exemplary turbofan engine, according to an exemplary embodiment of the present disclosure.

FIG. 2 is a schematic, cross-sectional view of an exemplary heat exchanger assembly that may be used with the turbofan engine shown in FIG. 1.

FIG. 3 is a schematic, cross-sectional view of another exemplary heat exchanger assembly that may be used with the turbofan engine shown in FIG. 1.

FIG. 4 is a schematic, cross-sectional view of yet another exemplary heat exchanger assembly that may be used with the turbofan engine shown in FIG. 1.

FIG. 5 is a perspective view of an exemplary bypass duct opening that may be used with the heat exchanger assembly shown in FIGS. 2-4.

FIG. 6 is a schematic view of an exemplary oil cooling system that may be used with the turbofan engine shown in FIG. 1.

Unless otherwise indicated, the drawings provided herein are intended to illustrate features of embodiments of the present disclosure. It is believed that these features can be applied in a wide variety of systems including one or more embodiments of the present disclosure. Accordingly, the drawings are not intended to include all of the conventional features known to those of skill in the art that are required to practice the embodiments disclosed herein.

Detailed Description

In the following specification and claims, reference will be made to a number of terms which shall be defined to have the following meanings.

The singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

"optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about", "approximately" and "approximately", are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of a tool for measuring the value. Here, and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all subranges subsumed therein unless context or language indicates otherwise.

Embodiments of an oil cooling system as described herein provide a multi-cooling path heat exchanger assembly that facilitates cooling engine oil that experiences high heat demand during both low and high speed engine operating conditions. Specifically, the heat exchanger assembly includes a cooling channel that receives a flow of oil to be cooled. The heat exchanger assembly also includes a first refrigerant flow conduit in flow communication with the Variable Bleed Valve (VBV) system such that a VBV discharge flow is provided as refrigerant during low speed engine operating conditions, and a second refrigerant flow conduit in flow communication with the bypass conduit such that a fan jet air flow is provided as refrigerant during high speed engine operating conditions. In various embodiments, the heat exchanger assembly further comprises an ejector, such that the refrigerant flowing through the heat exchanger may be further controllable. In certain embodiments, the flow of refrigerant is discharged into a bypass conduit, while in other embodiments, the flow of refrigerant is discharged to a thermal management system for further thermal management of the engine component. The heat exchanger assembly may also be coupled to additional heat exchanger assemblies to form a larger oil cooling system within the bypass duct. In addition to thermal management of the engine oil, the heat exchanger assembly also facilitates boundary layer suction of the fan jet air at the bypass duct, thereby increasing propulsive thrust therethrough.

FIG. 1 is a schematic cross-sectional view of a gas turbine engine in accordance with an exemplary embodiment of the present disclosure. In the exemplary embodiment, the gas turbine engine is a high bypass turbofan jet engine 110, referred to herein as "turbofan engine 110". As shown in FIG. 1, turbofan engine 110 defines an axial direction A (extending parallel to a longitudinal centerline 112 provided for reference) and a radial direction R (extending perpendicular to longitudinal centerline 112). Generally speaking, turbofan engine 110 includes a fan case assembly 114 and a gas turbine engine 116 disposed downstream of fan case assembly 114.

The gas turbine engine 116 includes a substantially tubular outer casing 118, the outer casing 118 defining an annular inlet 120. The outer shell 118 encloses in serial flow relationship: a compressor section including a booster or Low Pressure (LP) compressor 122 and a High Pressure (HP) compressor 124; a combustion section 126; a turbine section including a High Pressure (HP) turbine 128 and a Low Pressure (LP) turbine 130; and a jet discharge nozzle section 132. A High Pressure (HP) shaft or spool 134 drivingly connects HP turbine 128 to HP compressor 124. A Low Pressure (LP) shaft or spool 136 drivingly connects the LP turbine 130 to the LP compressor 122. Together, the compressor section, combustion section 126, turbine section, and discharge nozzle section 132 define an air flow path 138.

In the exemplary embodiment, fan case assembly 114 includes a fan 140 having a plurality of fan blades 142 coupled to a disk 144 in a spaced-apart manner. As depicted, the fan blades 142 extend generally outward from the disk 144 in the radial direction R. The fan blades 142 and the disk 144 are rotatable together about the longitudinal centerline 112 by the LP shaft 136.

Still referring to the exemplary embodiment of FIG. 1, the disk 144 is covered by a rotatable forward hub 146, the forward hub 146 being aerodynamically contoured to promote airflow through the plurality of fan blades 142. Moreover, exemplary fan case assembly 114 includes an annular fan casing or nacelle 148 that circumferentially surrounds at least a portion of fan 140 and/or gas turbine engine 116. The nacelle 148 includes an inner radial surface 150 opposite the outer engine casing 118. Nacelle 148 is supported relative to gas turbine engine 116 by an Outlet Guide Vane (OGV) assembly 152. Moreover, a downstream section 154 of nacelle 148 may extend over an outer portion of gas turbine engine 116 to define a bypass airflow duct 156 between radially inner surface 150 and outer casing 118.

During operation of turbofan engine 110, a volume of air 158 enters turbofan engine 110 through nacelle 148 and/or an associated inlet 160 of fan case assembly 114. As air 158 travels across fan blades 142, a first portion of air 158 (known as fan jet air flow) indicated by arrow 162 is directed or routed into bypass air flow conduit 156 and a second portion of air 158 indicated by arrow 164 is directed or routed into air flow path 138, or more specifically booster compressor 122. The ratio between the first portion of air 162 and the second portion of air 164 is commonly referred to as the bypass ratio. The pressure of the second portion of air 164 then increases as compressor air 166 as it is routed through booster compressor 124 and HP compressor 124 and into combustion section 126, where the second portion of air 164 is mixed with fuel and burned to provide combustion gases 168.

The combustion gases 168 are routed through the HP turbine 128, where a portion of the thermal and/or kinetic energy from the combustion gases 168 is extracted via successive stages of HP turbine stator vanes 170 coupled to the outer casing 118 and HP turbine rotor blades 172 coupled to the HP shaft or spool 134, thus causing the HP shaft or spool 134 to rotate, thereby supporting operation of the HP compressor 124. The combustion gases 168 are then sent through the LP turbine 130, where a second portion of the thermal and kinetic energy is extracted from the combustion gases 168 via successive stages of LP turbine stator vanes 174 coupled to the outer casing 118 and LP turbine rotor blades 176 coupled to the LP shaft or spool 136, thus causing the LP shaft or spool 136 to rotate, thereby supporting operation of the booster compressor 122 and/or rotation of the fan 140. The combustion gases 168 are then routed through the jet exhaust nozzle section 132 of the gas turbine engine 116 to provide propulsive thrust. The HP turbine 128, the LP turbine 130, and the jet exhaust nozzle section 132 at least partially define a hot gas path 178 for routing the combustion gases 168 through the gas turbine engine 116. At the same time, as fan jet air 162 is routed through bypass air flow duct 156 (including through outlet guide vane assembly 152 prior to its discharge from fan nozzle discharge section 180 of turbofan engine 110), which also provides propulsive thrust, the pressure of fan jet air 162 increases significantly.

In the exemplary embodiment, turbofan engine 110 also includes a Variable Bleed Valve (VBV) system 182 that is coupled in flow communication between LP compressor 122 and HP compressor 124. During engine operation at low speeds, for example, during engine start-up conditions, compressor air 166 channeled through LP compressor 122 is extracted through VBV system 182 and discharged from turbofan engine 110 through bypass airflow duct 156. At high speed engine operation, the VBV system 182 is closed and compressor air 166 is channeled towards HP compressor 124. Moreover, in the exemplary embodiment, turbofan engine 110 includes an oil cooling system 184 that is coupled in flow communication with VBV system 182 and bypass airflow duct 156. As discussed further below with reference to FIGS. 2-6, the oil cooling system 184 facilitates extracting heat from an engine oil flow (not shown) within the turbofan engine 110 via the airflow within the VBV system 182 and the bypass airflow conduit 156.

However, it should be appreciated that the exemplary turbofan engine 110 depicted in FIG. 1 is by way of example only, and that in other exemplary embodiments, the turbofan engine 110 may have any other suitable configuration. It should also be appreciated that, in still other exemplary embodiments, aspects of the present disclosure may be incorporated into any other suitable gas turbine engine. For example, in other exemplary embodiments, aspects of the present disclosure may be incorporated into, for example, turboprop engines, military engines, and sea-based or land-based aero-derivative engines.

FIG. 2 is a schematic, cross-sectional view of an exemplary heat exchanger assembly 200 that may be used with the oil cooling system 184 of turbofan engine 110 (shown in FIG. 1). In the exemplary embodiment, heat exchanger assembly 200 is a tubular heat exchanger. In some embodiments, the heat exchanger assembly 200 is a finned tube heat exchanger. In alternative embodiments, heat exchanger assembly 200 may include any other heat transfer features, such as strakes, dimples, and other features that enable heat exchanger assembly 200 to function as described herein. The heat exchanger assembly 200 includes a plurality of cooling passages 202 positioned within a recess 204, the recess 202 defined within the engine outer casing 118 and adjacent to the bypass duct 156. In the exemplary embodiment, cooling channel 202 is substantially circular in cross-section. Additionally or alternatively, the cooling channels 202 may have any other cross-section that enables the heat exchanger assembly 200 to function as described herein. Further, the cooling channels 202 may vary in cross-sectional area and/or in pitch across the refrigerant flow path. The recess 204 opens into the bypass duct 156 at locations 206 and 208 within the outer engine case 118 such that the recess 204 is in flow communication with the bypass duct 156. Additionally, the depression 204 is open to the VBV system 182 at a location 210 within the engine outer casing 118, such that the depression 204 is also in flow communication with the VBV system 182.

The heat exchanger assembly 200 further includes at least one first refrigerant flow conduit 212 having a first inlet 214 and a first outlet 216 such that a first fluid flow path 218 is defined therethrough, wherein the cooling channel 202 is disposed between the first inlet 214 and the first outlet 216. A first inlet 214 and a first outlet 216 are further defined within the VBV system 182. Specifically, the VBV system 182 includes a conduit 220, the conduit 220 extending between the LP compressor 122 (shown in FIG. 1) and the engine outer casing 118. A first inlet 214 is defined within VBV conduit 220 upstream of cooling passage 202, and a first outlet 216 is defined within engine outer casing 118 downstream of cooling passage 202, such that a first fluid flow path 218 is defined from VBV conduit 220, through cooling passage 202, to bypass conduit 156.

The heat exchanger assembly 200 further includes at least one second refrigerant flow conduit 222 having a second inlet 224 and a second outlet 226 such that a second fluid flow path 228 is defined therethrough, wherein the cooling channel 202 is disposed between the second inlet 224 and the second outlet 226. A second inlet 224 and a second outlet 226 are further defined within the bypass conduit 156. Specifically, a second inlet 224 is defined within the engine outer casing 118 upstream of the cooling passage 202, and a second outlet 226 is defined within the outer casing recess 204 downstream of the cooling passage 202, such that a second fluid flow path 228 is defined from the bypass conduit 156, through the cooling passage 202, and back to the bypass conduit 156. In the exemplary embodiment, first outlet 216 substantially corresponds with second inlet 224 such that first fluid flow path 218 exits heat exchanger assembly 200 at the same location where second fluid flow path 228 entered heat exchanger assembly 200.

In the exemplary embodiment, heat exchanger assembly 200 also includes at least one injector 230 within recess 204 and downstream from cooling passage 202 in a second fluid flow path 228. Additionally, a filter 232 is positioned in the second fluid flow path 228 between the cooling passage 202 and the injector 230. In some embodiments, the filter 232 may include a perforated plate having differently sized apertures defined therein to help balance the flow across the second outlet 226 such that the flow across the second outlet 226 occurs along the entire outlet region. Moreover, in the exemplary embodiment, heat exchanger assembly 200 includes at least one turning vane 233 disposed at first inlet 214 that facilitates channeling and distributing flow through heat exchanger assembly 200. In alternative embodiments, the heat exchanger assembly 200 has any other configuration that enables the heat exchanger assembly 200 to function as described herein.

During operation of turbofan engine 110, oil 234 flows through turbofan engine 110 where oil 234 accumulates heat, for example, from rotating components therein. The oil 234 is then directed through the heat exchanger assembly 200 and the plurality of cooling channels 202 for heat to be extracted therefrom. Specifically, when the heat exchanger assembly 200 is in the first operating mode, during low speed engine operation, pressurized VBV discharge air 236 is bled from the LP compressor 122 through the VBV system 182. The VBV discharge air 236 is directed into the first refrigerant flow conduit 212 at the first inlet 214, where the VBV discharge air 236 is used to cool the oil 234 within the heat exchanger assembly 200. For example, VBV discharge air 236 is directed through first refrigerant flow conduit 212 via first fluid flow path 218. In some embodiments, turning vane 233 facilitates directing first fluid flow path 218 through first inlet 214. VBV discharge air 236 then exits first refrigerant flow conduit 212 at first outlet 216, where it is discharged into bypass conduit 156 and exits turbofan engine 110. When the heat exchanger assembly 200 is in the second mode of operation, during high speed engine operation, the VBV system 182 is closed and does not bleed air from the LP compressor 122. Thus, to cool oil 234 flowing through heat exchanger assembly 200, a portion of fan jet air 162 (fan air 238) flowing through bypass duct 156 is channeled through heat exchanger assembly 200. Fan air 238 is channeled into second refrigerant flow conduit 222 at second inlet 224, wherein fan air 238 is utilized to cool oil 234 within heat exchanger assembly 200. For example, fan air 238 is channeled through second refrigerant flow conduit 222 via second fluid flow path 228. Fan air 238 then exits the second refrigerant flow conduit 222 at the second outlet 226 where it is discharged back into the bypass conduit 156 through the outer engine housing opening 208, thereby providing propulsive thrust.

In some embodiments, during high speed engine operation, fan air 238 is drawn through the second refrigerant flow conduit 222 by the ejector 230. High pressure bleed air 240 is extracted from the HP compressor 124 and used as a motive fluid, which is channeled through the ejector 230 to draw fan air 238 into the recess 204 and the heat exchanger assembly 200. The ejector 230 also allows the flow of fan air 238 to be controlled through the second refrigerant flow conduit 222 such that the amount of heat extracted from the oil 234 within the heat exchanger assembly 200 is controllable. For example, in one aspect, when a low flow of bleed air 240 is provided to the ejector 230, a lower fan air flow 238 will be drawn through the heat exchanger assembly 200, thereby providing less refrigerant and reducing heat transfer from the oil 234 to the fan air 238. While on the other hand, when a high flow of bleed air 240 is provided to the ejector 230, a higher fan air flow 238 will be drawn through the heat exchanger assembly 200, thereby providing more refrigerant and increasing the heat transfer from the oil 234 to the fan air 238. The bleed air 240 is then mixed with the fan air 238 downstream of the ejector 230, where the bleed air 240 is also discharged back into the bypass duct 156 through the outer engine case opening 208.

Additionally, a second inlet 224 of the heat exchanger assembly 200 is positioned at the outer engine casing 118 of the bypass duct 156, wherein a boundary layer of the fan jet air flow 162 may be formed. The boundary layer is a viscous fluid layer formed substantially proximate to a surface (such as the engine outer casing 118) that contains a fluid flow (such as the fan jet air 162). The presence of the boundary layer creates drag on fan jet air 162, thereby reducing propulsive thrust and engine efficiency. In addition to facilitating cooling of the oil 234, the heat exchanger assembly 200 facilitates bleeding or otherwise removing a boundary layer formed at the engine outer casing 118 through the second refrigerant flow conduit 222 and improves propulsive thrust and engine efficiency. In some embodiments, the ejector 230 also facilitates bleeding off a boundary layer of the fan jet air 162 through the second refrigerant flow conduit 222.

Moreover, in the exemplary embodiment, heat exchanger assembly 200 is illustrated within bypass duct 156 of a ducted turbofan engine. Additionally or alternatively, the heat exchanger assembly 200 may also be used within an unducted turbofan engine, wherein the fan 140 (shown in FIG. 1) may be configured at an aft portion of the engine 116 (shown in FIG. 1) such that the air flow 118 adjacent the engine outer casing 118 is drawn into the heat exchanger assembly 200. Further, as a modification, the heat exchanger assembly 200 may be formed within the turbofan engine 110.

FIG. 3 is a schematic, cross-sectional view of another exemplary heat exchanger assembly 300 that may be used with the oil cooling system 184 of turbofan engine 110 (shown in FIG. 1). Similar to the heat exchanger assembly 200 (shown in FIG. 2), in the exemplary embodiment, heat exchanger assembly 300 is a tubular heat exchanger that includes a cooling passage 202 positioned within a recess 302, which recess 302 is defined within engine outer casing 118 and is adjacent to bypass duct 156. Additionally, the first refrigerant flow conduit 212 defines a first fluid flow path 218 with the cooling channel 202 disposed between the first inlet 214 and the first outlet 216, and the second refrigerant flow conduit 222 includes the cooling channel 202 disposed between the second inlet 224 and the second outlet 226. However, in the exemplary embodiment, recess 302 opens to bypass duct 156 at a location 304 within outer engine casing 118 such that recess 302 is in flow communication with bypass duct 156. The recess 302 opens to the VBV system 182 at a location 306 within the engine outer casing 118 such that the recess 302 is in flow communication with the VBV system 182. Recess 302 also opens to thermal management system 308 at location 310 such that the recess is in flow communication with thermal management system 308. In addition, second refrigerant flow conduit 222 defines a second fluid flow path 312 between second inlet 224 and second outlet 226.

In the exemplary embodiment, when heat exchanger assembly 300 is in the second mode of operation during high speed engine operation. A portion of fan jet air 162 (fan air 314) flowing through bypass duct 156 is channeled through heat exchanger assembly 300. Fan air 314 is directed into second refrigerant flow conduit 224 at second inlet 222, where fan air 314 is used to cool oil 234 within heat exchanger assembly 300. For example, fan air 314 is channeled through second refrigerant flow conduit 222 via second fluid flow path 312. Fan air 314 then exits second refrigerant flow conduit 222 at second outlet 226 where it is directed to thermal management system 308, wherein fan air 314 is further used to cool other areas of turbofan engine 110. Because fan jet air 162 and fan air 314 may have particulates entrained therein, for example, during engine operation in dry weather, including sand and dirt, heat exchanger assembly 300 also includes filter 232, filter 232 filters out particulates so that particulates do not flow into thermal management system 308 and affect other engine components.

In some embodiments, during high speed engine operation, fan air 314 is drawn through the second refrigerant flow conduit 222 by the ejector 230, as explained above with reference to fig. 2. The bleed air 240 is then mixed with the fan air 314 downstream of the ejector 230, where the bleed air 240 is also directed to the thermal management system 308, wherein the fan air 314 and the bleed air 240 are further used to cool other areas of the turbofan engine 110. In this embodiment, the bleed air 240 has been filtered of particulates, and the ejector 230 is positioned downstream of the filter 232. In alternative embodiments, filter 232 may be positioned at any location that enables heat exchanger assembly 300 to function as described herein, for example, the filter may be positioned downstream of both cooling passage 202 and injector 230.

FIG. 4 is a schematic, cross-sectional view of yet another exemplary heat exchanger assembly 400 that may be used with an oil cooling system 184 of turbofan engine 110 (shown in FIG. 1). Similar to the heat exchanger assemblies 200 and 300 (shown in FIGS. 2 and 3, respectively), in the exemplary embodiment, heat exchanger assembly 400 is a finned tube heat exchanger that includes cooling passages 202 positioned within a recess 402, the recess 402 defined within engine outer casing 118 and adjacent to bypass duct 156. However, in the exemplary embodiment, recess 402 opens to bypass duct 156 at locations 404 and 406 within outer engine casing 118 such that recess 402 is in flow communication with bypass duct 156. The heat exchanger assembly 400 includes only one refrigerant flow conduit, at least one refrigerant flow conduit 408, having an inlet 410 and an outlet 414 such that a fluid flow path 414 is defined therethrough, with the cooling channel 202 disposed between the inlet 410 and the outlet 412. An inlet 410 and an outlet 412 are further defined within the bypass conduit 156. Specifically, an inlet 410 is defined within the engine outer casing 118 upstream of the cooling passage 202, and an outlet 412 is defined within the outer casing recess 204 downstream of the cooling passage 202, such that a fluid flow path 414 is defined from the bypass duct 156, through the cooling passage 202, and back to the bypass duct 156.

In the exemplary embodiment, heat exchanger assembly 400 also includes an ejector 416 within recess 402 and downstream from cooling passage 202 in a fluid flow path 414. The injector 416 is a Y-shaped injector having a first inlet 418 and a second inlet 420 and an outlet 422. Specifically, the injector first inlet 418 is coupled in flow communication with the VBV system 182, and the injector second inlet 420 is coupled in flow communication with a compressor bleed system (not shown). Moreover, in the exemplary embodiment, heat exchanger assembly 400 includes at least one turning vane 423 disposed at outlet 412 that facilitates directing and distributing flow through heat exchanger assembly 400.

During operation of turbofan engine 110, oil 234 is channeled through heat exchanger assembly 400 and the plurality of cooling channels 202 for heat to be extracted therefrom. Specifically, with the heat exchanger assembly 400 in the first operating mode during low speed engine operation, pressurized VBV discharge air 236 is bled from the LP compressor 122 through the VBV system 182 and directed to the ejector 416 for use as motive fluid to draw in ambient air 424 from the bypass conduit 156. Ambient air 424 is directed into the refrigerant flow conduit 408 at the inlet 410 where the ambient air 424 is used to cool the oil 234 within the heat exchanger assembly 200. For example, ambient air 424 is channeled through refrigerant flow conduit 408 via fluid flow path 414. Ambient air 424 then exits the refrigerant flow conduit 408 at the outlet 412, where the ambient air 424 is discharged into the bypass conduit 156 at the engine outer housing opening 406 along with VBV discharge air 236 from the ejector 416. In some embodiments, the turning vanes 423 help direct the fluid flow path 414 through the outlet 412. The heat exchanger assembly 400 is in a second mode of operation during high speed engine operation, wherein the VBV system 182 is off and air is not bled from the LP compressor 122. Thus, to cool oil 234 flowing through heat exchanger assembly 400, bleed air 240 is extracted from HP compressor 124 and directed to ejector 416 for use as a motive fluid to draw in a portion of fan jet air 162 (fan air 426) flowing through bypass duct 156. Similar to the ambient air 424, fan air 426 is directed into the refrigerant flow conduit 408 at the inlet 410, where the fan air 426 is used to cool the oil 234 within the heat exchanger assembly 400. For example, fan air 426 is channeled through refrigerant flow conduit 408 via fluid flow path 414. The fan air 426 then exits the refrigerant flow conduit 408 at the outlet 412, where the fan air 426 is discharged back into the bypass conduit 156 at the outer engine case opening 406 along with the bleed air 240 from the ejector 416.

In an alternative embodiment, recess 402 opens into thermal management system 308 (shown in FIG. 3) at location 406 such that ambient air 424 and fan air 426 exiting refrigerant flow conduit 408 at outlet 412 are channeled to thermal management system 308 wherein such air is further used to cool other areas of turbofan engine 110.

FIG. 5 is a perspective view of an exemplary bypass duct opening 500 that may be used with heat exchanger assemblies 200, 300, and 400 (shown in FIGS. 2-4). 2-4). In the exemplary embodiment, plurality of tubular cooling passages 202 are recessed within an engine outer casing 118, and engine outer casing 118 includes a bypass duct opening 500 formed therein. The opening 500 may be the opening 206 illustrated in fig. 2, or the opening 304 illustrated in fig. 3, or the opening 404 illustrated in fig. 4. In alternative embodiments, the cooling passages 202 may be flush with the engine outer casing 118 or elevated above the engine outer casing 118 to further facilitate cooling the oil therein. Additionally or alternatively, opening 500 may include at least one cap 502 such that a plurality of smaller openings 504 are defined. The cap 502 and the opening 504 facilitate regulating and controlling the amount of boundary layer bleed from within the bypass duct 156, as further described above with reference to FIG. 2. By providing a plurality of openings 504 spaced apart by a predetermined distance, a boundary layer formed within bypass duct 156 of fan jet air 162 (shown in FIG. 1) is allowed to develop over cap 502 and then removed, and allowed to regenerate.

FIG. 6 is a schematic view of an exemplary oil cooling system 600 that may be used with turbofan engine 110 (shown in FIG. 1). The oil cooling system 600 includes a radially inner first heat exchanger assembly 602 positioned at the outer engine casing 118 and adjacent to the bypass duct 156. In the exemplary embodiment, first heat exchanger assembly 602 is a finned tube heat exchanger in flow communication with VBV system 182 and bypass conduit 156, such as heat exchanger assemblies 200, 300, and 400 described above in FIGS. 2-4, for extracting heat from oil 234. Additionally, the oil cooling system 600 includes a radially outer second heat exchanger assembly 604 and a third Outlet Guide Vane (OGV) heat exchanger assembly 606 to facilitate further thermal management of the oil flow 234. Each of the heat exchanger assemblies 602, 604, and 606 are coupled in flow communication with each other by a manifold system 608, the manifold system 608 including at least one conduit 610 through which the oil 234 is directed. The oil cooling system 600 also includes a bypass valve 612 positioned between the first heat exchanger assembly 602 and the OGV heat exchanger assembly 606 such that the oil 234 can bypass the second heat exchanger assembly 604 and the third heat exchanger assembly 606.

In the exemplary embodiment, second heat exchanger assembly 604 is positioned at radially inner surface 150 of outer nacelle 148 and adjacent to bypass duct 156. The second heat exchanger assembly 604 may be a surface cooler heat exchanger. Alternatively, the second heat exchanger assembly 604 may be a tubular heat exchanger similar to the heat exchanger assemblies 200, 300, and 400 described above in fig. 2-4. However, in the exemplary embodiment, second heat exchanger assembly 604 will not be coupled in flow communication with VBV system 182. Second heat exchanger assembly 604 is coupled in flow communication with bypass conduit 156 such that a portion of fan jet air 162 drawn through by the ejector (not shown) is used for refrigerant. The OGV heat exchanger assembly 606 is positioned on the OGV assembly 152 and can be a surface cooler heat exchanger such that fan jet air 162 is used for the refrigerant. In alternative embodiments, the first, second, and third heat exchanger assemblies 602, 604, 606 may have any other configuration that enables the oil cooling system 600 to function as described herein.

During operation of turbofan engine 110, oil flow 234 is channeled through oil cooling system 600 for thermal management. Specifically, the oil flow 234 is channeled to the first heat exchanger assembly 602 via an inlet connection 614 and a conduit 610 of the header system 608. At the first heat exchanger assembly 602, heat is extracted from the oil 234 by a portion of the VBV discharge air 236 used as refrigerant during low speed engine operation and the first mode of operation or the fan jet air 162 used as refrigerant during high speed engine operation and the second mode of operation. During low oil heat demand, or during low speed engine operation, the oil flow 234 may bypass the second and third heat exchanger assemblies 604, 604 through the bypass valve 612. However, during high oil heat demand, the oil 234 is then directed through a header system 608 and conduit 610 to the OGV heat exchanger assembly 606 and the second heat exchanger assembly 604, wherein the fan jet air 162 serves as the refrigerant for extracting heat from the oil 234. After cooling, the oil 234 is directed out of the oil cooling system 600 and to the engine 116 at an outlet connection 616 of the header system 608.

The above-described embodiments of the oil cooling system provide a multiple cooling path heat exchanger assembly that facilitates cooling engine oil that experiences high heat demand during both low and high speed engine operating conditions. Specifically, the heat exchanger assembly includes a cooling channel that receives a flow of oil to be cooled. The heat exchanger assembly further includes a first refrigerant flow conduit in flow communication with the VBV system such that a VBV discharge flow is provided as refrigerant during low speed engine operating conditions, and a second refrigerant flow conduit in flow communication with the bypass conduit such that a fan jet air flow is provided as refrigerant during high speed engine operating conditions. In various embodiments, the heat exchanger assembly further comprises an ejector, such that the refrigerant flowing through the heat exchanger may be further controllable. In certain embodiments, the flow of refrigerant is discharged into a bypass conduit, while in other embodiments, the flow of refrigerant is discharged to a thermal management system for further thermal management of the engine component. The heat exchanger assembly may also be coupled to additional heat exchanger assemblies to form a larger oil cooling system within the bypass duct. In addition to thermal management of the engine oil, the heat exchanger assembly also facilitates boundary layer suction of the fan jet air at the bypass duct, thereby increasing propulsive thrust therethrough.

Exemplary technical effects of the methods, systems, and devices described herein include at least one of: (a) increasing thermal control of engine oil during low speed engine operation; (b) increasing thermal control of engine oil during high speed engine operation; (c) supporting a geared turbofan engine with high oil heat load; (d) supporting an unducted turbofan engine; (e) supporting turbofan engine retrofitting; (f) increasing boundary layer suction for fan jet air flow; (g) reducing the weight of the engine; and (h) improving engine efficiency.

Exemplary embodiments of methods, systems, and apparatus for an oil cooling system are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the method may also be used in conjunction with other systems and related methods that require thermal control, and is not limited to practice with only the systems and methods described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many other applications, equipment, and systems that may benefit from thermal control.

Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the present disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

This written description uses examples to disclose embodiments, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.