阅读说明：本技术 机翼安装下的飞行器和直接驱动发动机 (Wing mounted aircraft and direct drive engine ) 是由 托马斯·奥里·莫尼斯 兰迪·M·沃德雷尔 杰弗里·唐纳德·克莱门茨 布兰登·韦恩·米勒 于 2018-01-17 设计创作，主要内容包括：本公开涉及一种燃气涡轮发动机,该燃气涡轮发动机限定径向方向、纵向方向和周向方向,沿着纵向方向的上游端和下游端,以及沿着纵向方向延伸的轴向中心线。燃气涡轮发动机包括风扇组件,该风扇组件包括可旋转地联接到风扇转子的多个风扇叶片,其中风扇叶片限定最大风扇直径和风扇压力比。燃气涡轮发动机进一步包括低压(LP)涡轮,该低压(LP)涡轮限定大体沿着纵向方向通过其中的核心流动路径。核心流动路径限定相对于轴向中心线的最大外部流动路径直径。燃气涡轮发动机限定最大风扇直径与最大外部流动路径直径的风扇与涡轮直径比。风扇与涡轮直径比与风扇压力比之比为近似0.90以上。(The present disclosure relates to a gas turbine engine defining a radial direction, a longitudinal direction, and a circumferential direction, upstream and downstream ends along the longitudinal direction, and an axial centerline extending along the longitudinal direction. The gas turbine engine includes a fan assembly including a plurality of fan blades rotatably coupled to a fan rotor, wherein the fan blades define a maximum fan diameter and a fan pressure ratio. The gas turbine engine further includes a Low Pressure (LP) turbine defining a core flowpath therethrough generally along the longitudinal direction. The core flowpath defines a maximum outer flowpath diameter relative to the axial centerline. The gas turbine engine defines a fan to turbine diameter ratio of a maximum fan diameter to a maximum external flow path diameter. The ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 0.90 or greater.)

1. A gas turbine engine defining a radial direction, a longitudinal direction, and a circumferential direction, upstream and downstream ends along the longitudinal direction, and an axial centerline extending along the longitudinal direction, the gas turbine engine comprising:

A fan assembly including a plurality of fan blades rotatably coupled to a fan rotor, the fan blades defining a maximum fan diameter and a fan pressure ratio; and

a Low Pressure (LP) turbine defining a core flowpath therethrough generally along the longitudinal direction, wherein the core flowpath defines a maximum outer flowpath diameter relative to the axial centerline, and wherein the gas turbine engine defines a fan-to-turbine diameter ratio of the maximum fan diameter to the maximum outer flowpath diameter, and wherein a ratio of the fan-to-turbine diameter ratio to the fan pressure ratio is approximately 0.90 or greater.

2. The gas turbine engine of claim 1, wherein the fan assembly defines a fan pressure ratio of between approximately 1.0 and approximately 1.8.

3. the gas turbine engine of claim 2, wherein a ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 1.20 or greater at fan pressure ratios of approximately 1.50 or less.

4. The gas turbine engine of claim 2, wherein a ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 1.05 or greater at fan pressure ratios between approximately 1.50 and approximately 1.60.

5. The gas turbine engine of claim 1, wherein a ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 0.90 or greater at fan pressure ratios between approximately 1.60 and approximately 1.80.

6. The gas turbine engine of claim 1, wherein the fan to turbine diameter ratio is approximately 1.8 or greater.

7. The gas turbine engine of claim 1, wherein the LP turbine and the fan rotor of the fan assembly are rotatably coupled in a direct drive configuration via a drive shaft.

8. The gas turbine engine of claim 1, wherein the LP turbine defines a rotor having more than six stages.

9. The gas turbine engine of claim 8, wherein the LP turbine defines the maximum outer flowpath diameter at two or more rotating stages at a most downstream end of the LP turbine.

10. The gas turbine engine of claim 9, wherein the LP turbine defines the maximum outer flowpath diameter at more than three rotational stages at the most downstream end of the LP turbine.

11. The gas turbine engine of claim 1, further comprising containment shroud, wherein the containment shroud is coupled to a casing of the engine that extends generally along the longitudinal direction, wherein the containment shroud extends at least partially along the circumferential direction from a top dead center datum line in a clockwise and/or counterclockwise direction.

12. The gas turbine engine of claim 11, wherein said containment shroud extends less than approximately 60 degrees clockwise and/or counterclockwise along said circumferential direction from said top dead center reference line.

13. An aircraft defining a longitudinal direction, a latitudinal direction, and a transverse direction, the aircraft including a fuselage extending along the longitudinal direction, with more than one pair of wings attached to the fuselage along the transverse direction, the aircraft comprising:

A wing extending from the fuselage, the wing including a pylon, and wherein the wing defines a leading edge and a trailing edge, and wherein the leading edge defines a forward plane extending along a radial direction, and wherein the trailing edge defines a rearward plane extending along the radial direction; and

A gas turbine engine coupled to the pylon of the wing, wherein each engine comprises:

A fan assembly including a plurality of fan blades rotatably coupled to a fan rotor, the fan blades defining a maximum fan diameter and a fan pressure ratio; and

A Low Pressure (LP) turbine defining a core flowpath therethrough generally along the longitudinal direction, wherein the core flowpath defines a maximum outer flowpath diameter relative to the axial centerline, and wherein the gas turbine engine defines a fan-to-turbine diameter ratio of the maximum fan diameter to the maximum outer flowpath diameter, and wherein a ratio of the fan-to-turbine diameter ratio to the fan pressure ratio is approximately 0.90 or greater.

14. The aircraft of claim 13, wherein the LP turbine further defines a first turbine rotor at an extreme upstream end of the LP turbine and a last turbine rotor at an extreme downstream end of the LP turbine, and further wherein the LP turbine defines a turbine burst region inboard of the airfoil along the radial direction, the turbine burst region extending at a first angle from the axial centerline along a plane of rotation of the first turbine rotor toward the upstream end and at a second angle from the axial centerline along a plane of rotation of the last turbine rotor toward the downstream end.

15. The aircraft of claim 14, wherein the first angle of the turbine burst zone is approximately 15 degrees or less.

16. The aircraft of claim 14, wherein the second angle of the turbine burst zone is approximately 15 degrees or less.

17. The aircraft of claim 13, wherein the wing defines a wing shear center, and wherein the gas turbine engine further comprises:

An exhaust nozzle disposed downstream of the LP turbine, wherein the exhaust nozzle defines a downstream-most end, and wherein the downstream-most end is approximately equal to the airfoil shear center of the airfoil along the longitudinal direction.

18. The aircraft of claim 13 wherein the fan assembly of the gas turbine engine defines a fan pressure ratio of between approximately 1.0 and approximately 1.8.

19. The aircraft of claim 13, wherein the ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 1.20 or greater at fan pressure ratios of approximately 1.50 or less.

20. The aircraft of claim 13 wherein the fan to turbine diameter ratio of the gas turbine engine is approximately 1.8 or greater.

Technical Field

The present subject matter relates generally to gas turbine engine architectures.

Background

Aircraft, such as commercial passenger aircraft, typically include a gas turbine engine mounted forward of a leading edge of a wing of the aircraft. In known configurations, at least the rotating components of the gas turbine engine (e.g., the turbine section, the compressor section, and the fan assembly) are disposed forward of the leading edge to mitigate risk of failure relative to the rotor.

In a direct drive gas turbine engine, a Low Pressure (LP) turbine and a fan assembly are each coupled to an LP shaft to define an LP spool without a reduction gearbox therebetween (i.e., the LP turbine and the fan assembly rotate at approximately the same rotational speed). In contrast, an indirect drive gas turbine engine (e.g., a geared turbofan engine) includes a reduction gearbox disposed between the fan assembly and the LP turbine rotor. The gearbox typically proportionally reduces the speed of the fan assembly relative to the LP turbine rotor. Thus, the indirectly driven LP turbine rotor typically rotates at a greater speed than the directly driven LP turbine rotor. For example, some indirectly driven LP turbines may rotate at approximately three times the speed of a directly driven LP turbine.

However, the increased risk to the engine and aircraft due to rotor failure (e.g., disk, hub, drum, seals, impellers, blades, and/or shims) at least partially offsets the increased efficiency due to the faster rotating LP turbine and the relatively lower speed fan assembly. Thus, known indirect drive LP turbines typically require additional structure to at least reduce this risk to a risk comparable to a relatively low speed direct drive turbine.

Still further, the indirect drive motor architecture introduces additional systems and components (e.g., a reduction gearbox) relative to direct drive motors that create other performance losses and aircraft risks. For example, in addition to the risk from the relatively high speed LP turbine, the reduction gearbox adds weight, complexity, and new failure modes to the engine and aircraft.

Accordingly, there is a need for an aircraft and engine system that may include structural and risk benefits from a relatively low speed LP turbine while also improving aircraft efficiency.

Disclosure of Invention

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

the present invention relates to a gas turbine engine defining a radial direction, a longitudinal direction, and a circumferential direction, an upstream end and a downstream end along the longitudinal direction, and an axial centerline extending along the longitudinal direction. The gas turbine engine includes a fan assembly including a plurality of fan blades rotatably coupled to a fan rotor, wherein the fan blades define a maximum fan diameter and a fan pressure ratio. The gas turbine engine further includes a Low Pressure (LP) turbine defining a core flowpath therethrough generally along the longitudinal direction. The core flowpath defines a maximum outer flowpath diameter relative to the axial centerline. The gas turbine engine defines a fan to turbine diameter ratio of a maximum fan diameter to a maximum external flow path diameter. The ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 0.90 or greater.

In various embodiments, the fan assembly defines a fan pressure ratio between approximately 1.0 and approximately 1.8. In various embodiments, the ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 1.20 or greater at fan pressure ratios of approximately 1.50 or less. In one embodiment, the ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 1.05 or greater at fan pressure ratios between approximately 1.50 and approximately 1.60. In another embodiment, the ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 0.90 or greater at fan pressure ratios between approximately 1.60 and approximately 1.80.

In another embodiment, the fan to turbine diameter ratio is approximately 1.8 or greater.

In yet another embodiment, the LP turbine and the fan rotor of the fan assembly are rotatably coupled in a direct drive configuration via a drive shaft.

In various embodiments, the LP turbine defines more than six stages of rotors. In one embodiment, the LP turbine defines a maximum outer flowpath diameter at more than two rotating stages at a most downstream end of the LP turbine. In another embodiment, the LP turbine defines a maximum outer flowpath diameter at more than three rotational stages at a most downstream end of the LP turbine.

In various embodiments, the gas turbine engine further comprises containment shroud (containment shroud) coupled to a casing of the engine extending generally in the longitudinal direction, wherein the containment shroud extends at least partially in the circumferential direction from the top dead center datum line in a clockwise and/or counterclockwise direction. In one embodiment, the containment shroud extends clockwise and/or counterclockwise along the circumferential direction from the top dead center reference line less than approximately 60 degrees.

Another aspect of the present disclosure is directed to an aircraft defining a longitudinal direction, a latitudinal direction, and a transverse direction, the aircraft including a fuselage extending along the longitudinal direction, with more than one pair of wings attached to the fuselage along the transverse direction. An aircraft includes wings extending from a fuselage and a gas turbine engine. The airfoil includes a pylon to which the gas turbine engine is coupled. The airfoil defines a leading edge and a trailing edge, wherein the leading edge defines a forward plane extending in a radial direction and the trailing edge defines a rearward plane extending in the radial direction. The engine includes a fan assembly and a Low Pressure (LP) turbine. The fan assembly includes a plurality of fan blades rotatably coupled to a fan rotor. The fan blades define a maximum fan diameter and a fan pressure ratio. The LP turbine defines a core flow path therethrough generally along the longitudinal direction. The core flowpath defines a maximum outer flowpath diameter relative to the axial centerline. The gas turbine engine defines a fan-to-turbine diameter ratio of a maximum fan diameter to a maximum outer flow path diameter, wherein a ratio of the fan-to-turbine diameter ratio to the fan pressure ratio is approximately 0.90 or greater.

In various embodiments of the aircraft, the LP turbine further defines a first turbine rotor at an upstream-most end of the LP turbine and a last turbine rotor at a downstream-most end of the LP turbine. The LP turbine defines a turbine burst region inboard of the airfoil in a radial direction, wherein the turbine burst region extends at a first angle from the axial centerline along a plane of rotation of the first turbine rotor toward the upstream end and at a second angle from the axial centerline along a plane of rotation of the last turbine rotor toward the downstream end.

In one embodiment, the first angle of the turbine burst zone is approximately 15 degrees or less.

In another embodiment, the second angle of the turbine burst zone is approximately 15 degrees or less.

In yet another embodiment, the airfoil defines an airfoil shear center, and wherein the gas turbine engine further comprises an exhaust nozzle disposed downstream of the LP turbine. The exhaust nozzle defines a downstream-most end, wherein the downstream-most end is approximately equal to an airfoil shear center of the airfoil in the longitudinal direction.

in yet another embodiment, a fan assembly of a gas turbine engine defines a fan pressure ratio between approximately 1.0 and approximately 1.8.

In yet another embodiment, the ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 1.20 or greater at fan pressure ratios of approximately 1.50 or less.

In yet another embodiment, a fan to turbine diameter ratio of the gas turbine engine is approximately 1.8 or greater.

These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Drawings

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures. Wherein:

FIG. 1 is a perspective view of an exemplary embodiment of an aircraft including a direct drive engine, according to aspects of the present disclosure;

FIG. 2 is a cross-sectional view of an exemplary embodiment of a gas turbine engine attached to a wing and pylon of an aircraft;

FIG. 3 is a cross-sectional view of an exemplary embodiment of a LP turbine of the engine shown in FIGS. 1-2;

FIG. 4 is a cross-sectional view of another exemplary embodiment of a gas turbine engine attached to a wing and pylon of an aircraft; and

FIG. 5 is a plan view of an exemplary embodiment of the aircraft shown in FIGS. 1-4.

Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention.

Detailed Description

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

as used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one element from another, and are not intended to denote the position or importance of a single element.

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, and "downstream" refers to the direction to which the fluid flows. Unless otherwise specified, "downstream" and "upstream" refer to the general direction of fluid flow of air or generated combustion gases through the core flow path of the engine from the inlet of the compressor section to the outlet of the turbine section.

Embodiments of an engine and aircraft are generally provided that include a direct drive gas turbine engine that may include structural and risk benefits from a lower speed LP turbine while also improving aircraft efficiency. The engine includes a fan assembly defining a maximum fan diameter and an LP turbine rotor defining a maximum outer flow path diameter, wherein the engine defines a ratio of the maximum fan diameter to the maximum outer flow path diameter to a fan pressure ratio that is approximately 0.90 or greater. In various embodiments, the foregoing engines and ratios may place the LP turbine under the wing of the aircraft, aft of the leading edge of the wing. In still other various embodiments, containment structures are further provided to mitigate the risk of aircraft associated with turbine rotor burst.

In contrast to indirect drive engine configurations with high speed LP turbines, the embodiments shown and described herein may improve aircraft efficiency without the added system, complexity, failure modes, or risk of an indirect drive engine. In various embodiments, for every 51 millimeters (mm) of displacement of the center of gravity of the gas turbine engine in the longitudinal direction toward the leading edge of the wing of the aircraft, an aircraft weight of approximately 318 kilograms (kg) may be reduced. In still other various embodiments, shifting the center of gravity of the gas turbine engine toward the leading edge of the wing may improve aircraft fuel combustion by 0.5% for every 51mm shift. The embodiments described herein may further eliminate the weight, parts, and risks that are characteristic of an indirect drive motor with respect to a reduction gearbox failure.

Referring now to FIG. 1, an exemplary embodiment of an aircraft 100 is generally provided. The aircraft 100 defines a longitudinal direction L, a latitudinal direction LT, and a transverse direction T, as well as an upstream end 99 and a downstream end 98 along the longitudinal direction L. The aircraft 100 includes a fuselage 110 extending generally in a longitudinal direction L. A pair of wings 120 each extend from the fuselage 110 of the aircraft 100. Each wing 120 includes a pylon 130, to which one or more gas turbine engines 10 (hereinafter "engines 10") are attached below the wing 120 (e.g., inward in a latitudinal direction LT). In the various embodiments shown and described herein, the exemplary embodiment of engine 10 defines a direct drive engine, wherein the low pressure turbine rotor is attached to the fan rotor without a reduction gearbox therebetween.

It should be understood that reference to "upstream-most end" or "upstream" is with respect to a component or part that is oriented toward the upstream end 99 as shown in the figures, and is generally understood in the art as the direction from which the fluid comes before and as it passes through the region, part or component in question. Similarly, references to "downstream-most end" or "downstream" are relative to a component or part toward the downstream end 98, and are generally understood in the art as the direction of travel of the fluid as it passes through the region, part, or component in question.

Referring now to FIG. 2, an exemplary embodiment of a portion of an aircraft 100 is generally provided. Fig. 2 may provide further details regarding the relative arrangement of the engines 10 to the wings 120 of the aircraft 100 such that overall aircraft efficiency is improved while defining the relative risk of direct drive engines and their mitigation. The engine 10 defines an axial centerline 12 extending along the longitudinal direction L, and a radial direction R extending from the axial centerline 12. As shown in FIG. 2, each airfoil 120 defines a leading edge 122 and a trailing edge 124. As schematically shown in fig. 2, the leading edge 122 of the airfoil 120 defines a forward plane 126 that extends along the latitudinal direction LT and the lateral direction T (shown in fig. 1). The trailing edge 124 of the wing 120 defines an aft plane 128 that extends along the latitudinal direction LT and the transverse direction T (shown in fig. 1).

In various embodiments, the airfoil 120 further defines an airfoil shear center 121. The airfoil shear center 121 defines the point through which shear loads pass without distortion of the airfoil 120. The wing shear center 121 may further define a center of twist when torsional loads are applied to the wing 120. As schematically shown in fig. 1, the wing shear center 121 may further define a wing shear center plane 123 extending along the latitudinal direction LT and the transverse direction T (shown in fig. 1).

Still referring to FIG. 2, engine 10 includes, in a serial flow arrangement along longitudinal direction L, a fan assembly 14, a compressor section 21, a combustor section 26, turbine sections 28,30, and an exhaust nozzle assembly 33. The engine 10 generally extends along a longitudinal direction L, wherein the exhaust nozzle assembly 33 defines a downstream-most end 35, and the downstream-most end 35 may be disposed approximately equal to the airfoil shear plane 123 along the longitudinal direction L. In various embodiments, providing the most downstream end 34 of the exhaust nozzle assembly 33 may further displace the engine 10 toward the wing shear center 121, for example at the Low Pressure (LP) turbine 30, thereby reducing a moment arm from the engine 10 acting from the wing shear center 121. Reducing the moment arm from the wing shear center 121 may further reduce the weight of the wing 120 and/or pylon 130, thereby improving aircraft efficiency. In one embodiment, LP turbine 30 is disposed inboard of airfoil 120 along latitudinal direction LT. LP turbine 30 is disposed between a forward plane 126 and an aft plane 128 of airfoil 120 in longitudinal direction L.

Compressor section 21 includes a Low Pressure (LP) compressor 22 and a High Pressure (HP) compressor 24, generally in a serial flow arrangement from an upstream end 99 to a downstream end 98. The turbine section generally includes HP turbine 28 and LP turbine 30 in a serial flow arrangement from an upstream end 99 to a downstream end 98. A combustion section 26 is disposed between HP compressor 24 and HP turbine 28. HP compressor 24 and HP turbine 28 define a HP spool with a HP shaft 34, HP shaft 34 rotatably coupling HP compressor 24 and HP turbine 28.

Fan assembly 14 includes a plurality of fan blades 42 rotatably coupled to fan rotor 15. The fan rotor 15 is rotatably coupled towards an upstream end 99 of the drive shaft 36 extending in the longitudinal direction L. The LP turbine 30 is coupled to the drive shaft 36 toward a downstream end 98 of the drive shaft 36. Together, fan assembly 14, LP compressor 22, drive shaft 36, and LP turbine 30 define an LP spool. In one embodiment, LP turbine 30 defines at least four rotating stages or rotors 40. In another embodiment, LP turbine 30 defines more than six rotating stages 40.

During operation of the engine 10, the drive motor begins to rotate the HP spool, which introduces air, schematically shown as arrow 81, into the core flow path 70 of the engine 10. Air 81 passes through successive stages of LP compressor 22 and HP compressor 24 and increases in pressure to define compressed air 82 that enters combustion section 26. Fuel is introduced into combustion section 26 and mixed with compressed air 82, and then ignited to generate combustion gases 83. Energy from the combustion gases 83 drives rotation of the HP turbine 28 and the LP turbine 30, as well as their respective HP and LP spools, and the fan assembly 14 and compressor section 21, each attached thereto. In one embodiment, the LP spool rotates about the axial centerline 12 at a speed of approximately 6000 Revolutions Per Minute (RPM) or less. In another embodiment, the LP spool rotates about the axial centerline 12 at speeds below approximately 4000 RPM.

the cycle of introducing air 81 into the core flow path 70, mixing with fuel, igniting, and producing combustion gases 83 provides energy to rotate the plurality of fan blades 42 about the axial centerline 12 of the engine 10. A portion of the air 81 passes through the bypass duct 60 defined between the nacelle 45 and the casing 18 of the engine 10. The casing 18 is substantially tubular and generally surrounds the compressor section 21, the combustion section 26, and the turbine sections 28,30 along the longitudinal direction L. In the embodiments described herein, the nacelle 45 may further include a fan housing. The housing 18 may further include a shroud that defines a generally aerodynamic flow path for the bypass duct 60.

still referring to fig. 2, fan blades 42 define a maximum fan diameter 43 along radial direction R. The maximum fan diameter 43 is generally from the tip to the tip of the diametrically opposed fan blades 42. Alternatively, the maximum fan diameter 43 may refer to an inner diameter of the nacelle 45, the nacelle 45 including a fan housing surrounding the fan blades 42. Fan assembly 14 of engine 10 further defines a fan pressure ratio (i.e., a ratio of fan discharge pressure to fan inlet pressure) measured generally downstream of fan blades 42 to upstream of fan blades 42. For example, the fan pressure ratio may be the ratio of the pressure downstream of the fan blade 42 schematically shown at point 39 to the pressure upstream of the fan blade 42 schematically shown at point 38. In various embodiments, engine 10 defines a fan pressure ratio of approximately 1.0 to approximately 1.8.

Referring now to FIG. 3, an exemplary embodiment of the LP turbine 30 of the engine 10 is generally provided. 1-3, the LP turbine 30 of the engine 10 further defines a core flow path 70 therethrough generally along the longitudinal direction L. The core flowpath 70 defines a maximum outer flowpath diameter 71 within the LP turbine 30 relative to the axial centerline 12. The engine 10 further defines a fan to turbine diameter ratio, wherein the fan to turbine diameter ratio is the ratio of the maximum fan diameter 43 to the maximum outer flow path diameter 71.

The engine 10 further defines a ratio of a fan to turbine diameter ratio to a fan pressure ratio that is approximately 0.90 or greater.

in various embodiments, the ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 1.20 or greater at fan pressure ratios of approximately 1.50 or less. In one embodiment, the ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 1.05 or greater at fan pressure ratios between approximately 1.50 and approximately 1.60. In another embodiment, the ratio of the fan to turbine diameter ratio to the fan pressure ratio is approximately 0.90 or greater at fan pressure ratios between approximately 1.60 and approximately 1.80. In various embodiments, the fan to turbine diameter ratio is approximately 1.8 or greater.

Still referring to fig. 1-3, the LP turbine 30 defines a plurality of rotating stages or rotors 40 disposed along the longitudinal direction L. In one embodiment, the LP turbine 30 defines a maximum outer flowpath diameter 71 at more than two rotating stages 40 (i.e., the last two rotors of the LP turbine 30) at the most downstream end of the LP turbine. In another embodiment, the LP turbine 30 defines a maximum outer flowpath diameter 71 at three or more rotating stages 40 at a most downstream end of the LP turbine 30.

Referring now to FIG. 4, another exemplary embodiment of a portion of the aircraft 100 shown in FIGS. 1-3 is generally provided. In the embodiment illustrated in FIG. 4, and in conjunction with FIGS. 1-3, the LP turbine 30 of the engine 10 defines a first turbine rotor 41 at an upstream-most end of the LP turbine 30, and a last turbine rotor 42 at a downstream-most end of the LP turbine 30. LP turbine 30 defines a turbine burst zone 140, turbine burst zone 140 extending along a plane of rotation 143 of first turbine rotor 41 at a first angle 141 toward upstream end 99 of gas turbine engine 10, and along a plane of rotation 144 of last turbine rotor 42 at a second angle 142 toward downstream end 98 of gas turbine engine 10. Each plane of rotation 143,144 extends along a radial direction R. Each plane of rotation 143,144 may further extend along a transverse direction T (shown in fig. 1).

Referring to FIG. 4, in one embodiment, the first angle 141 of the turbine burst zone 140 is approximately 15 degrees or less. In another embodiment, the first angle 141 of the turbine burst zone 140 is approximately 5 degrees or greater.

Still referring to FIG. 4, in one embodiment, the second angle 142 of the turbine burst zone 140 is approximately 15 degrees or less. In another embodiment, the second angle 142 of the turbine burst zone 140 is approximately 5 degrees or greater.

referring now to fig. 1-4, in various embodiments, a turbine burst region 140 inboard of the airfoil 120 along a latitudinal direction LT is defined within the forward plane 126 and the aft plane 128 of the airfoil 120 along a longitudinal direction L.

Along the latitudinal direction LT, and between the forward plane 126 and the aft plane 128 along the longitudinal direction L, defining a turbine burst region 140 inboard of the wing 120, the weight of the pylon 130 and the wing 120 may be reduced by displacing the engine 10 along the longitudinal direction L toward the wing shear center 121. Displacing the engine 10 toward the wing shear center 121 may reduce the weight of the aircraft 100, thereby increasing aircraft efficiency. While further defining a direct drive engine, the cantilever weight from the pylon 130 and engine 10 can be reduced due to the absence of a reduction gearbox towards the upstream end 99 of the engine 10, thereby increasing the moment arm from the wing shear center 121, and ultimately, reducing aircraft weight and inefficiency. By locating the turbine burst zone 140 within the forward and aft planes 126, 128 of the wing 120, the weight of the pylon 130 and wing 120 is reduced while also maintaining the risks and failure modes similar to and known among direct drive engines.

referring now to fig. 1-5, embodiments of an aircraft 100 and engine 10 are generally provided in which a containment shroud 150 is further defined. In FIG. 5, a plan view of aircraft 100 is provided along either plane of rotation 143, 144. The containment shroud 150 extends over the LP turbine 30 along a longitudinal direction L. In various embodiments, containment shroud 150 extends from first turbine rotor 41 through last turbine rotor 42 along longitudinal direction L. The containment shroud 150 provides retention of the rotor components of the LP turbine 30, which may be released following a rotor failure. The rotor components may include disks, hubs, drums, seals, impellers, blades, and/or spacers, or fragments thereof that may be generally ejected from the engine 10 within the turbine burst zone 140.

In various embodiments, the containment shroud 150 extends at least within the transverse turbine burst zone 139. The transverse turbine burst zone 139 may generally extend clockwise and/or counterclockwise from the top dead center datum line 13. The top dead center reference line 13 extends from the axial centerline 12 in the radial direction R. In one embodiment, the transverse turbine burst zone 139 extends below approximately 60 degrees clockwise and/or counterclockwise from the top dead center datum line 13.

In one embodiment, containment shroud 150 may be coupled to wing 120 of aircraft 100 as shown at first containment shroud 151. The first containment shroud 151 extends generally along the transverse direction T and within the transverse turbine burst zone 139. In another embodiment, containment shroud 150 may be coupled to casing 18 of engine 10 as shown at second containment shroud 152. The second containment shroud 152 extends at least partially in the circumferential direction C from a top dead center reference line 13, the top dead center reference line 13 extending from the axial centerline 12 of the engine 10. In various embodiments, the second containment shroud 152 extends in a clockwise and/or counterclockwise direction from the top dead center reference line 13 along the circumferential direction C. In yet another embodiment, the second containment shroud 152 may extend substantially circumferentially (e.g., approximately 360 degrees) around the LP turbine 30 along the circumferential direction C.

The containment shroud 150 may be constructed of, but is not limited to, a Ceramic Matrix Composite (CMC) material and/or a metal suitable for a gas turbine engine containment structure, such as, but not limited to, a nickel-based alloy, a cobalt-based alloy, an iron-based alloy, or a titanium-based alloy, wherein each alloy may include, but is not limited to, chromium, cobalt, tungsten, tantalum, molybdenum, and/or rhenium.

The containment shield 150 may further or alternatively comprise a solid foamed synthetic polymer. In one embodiment, the solid foamed synthetic polymer may comprise a synthetic elastomer, such as an elastomeric polyurethane. In another embodiment, the solid foamed synthetic polymer may comprise ethylene vinyl acetate and/or an olefin polymer.

In another embodiment, containment shield 150 is formed from a plurality of fabric sheets formed from a plurality of fibers. In each fabric sheet, the plurality of fibers may form a network of fibers (e.g., a woven network, a random or parallel nonwoven network, or another orientation). In particular, the containment shield 150 may be constructed of high strength and high modulus fibers, such as para-aramid synthetic fibers (e.g., KEVLAR fibers available from e.i. dupont de Nemours and Company), metal fibers, ceramic fibers, glass fibers, carbon fibers, boron fibers, terephthalamide fibers, aramid fibers, silicon carbide fibers, graphite fibers, nylon fibers, or mixtures thereof. Another example of a suitable fiber includes ultra high molecular weight polyethylene (e.g., SPECTRA fiber manufactured by Honeywell International inc.).

The fibers of the containment shroud 150 may have high tensile strength and a high modulus of high orientation, resulting in a very smooth fiber surface exhibiting a low coefficient of friction. When forming a fabric layer, such fibers typically exhibit poor energy transfer to adjacent fibers during intermittent transfer of energy or torque from the rotor failure of the LP turbine 30 to surrounding structures such as the skin 18 and/or the wing 120 of the aircraft 100.

The system shown in fig. 1-5 and described herein may improve the efficiency of an aircraft utilizing a direct drive gas turbine engine by reducing the moment arm from the wing shear center 121 to the upstream end 99 of the engine 10, thereby reducing the weight of the wing 120, pylon 130, and/or engine 10. Reducing the moment arm may be accomplished by defining a maximum outer flowpath diameter 71 of the LP turbine 30 associated with the maximum fan diameter 43. Still further, reducing the moment arm may be accomplished by defining a maximum outer flowpath diameter 71 at two or more rotating stages 40 at a most downstream end of the LP turbine 30 (e.g., two or more stages from a downstream end 98 of the engine 10). Moreover, the system disclosed herein may increase the efficiency of the aircraft 100 while utilizing a direct drive gas turbine engine, while avoiding the additional subsystems, risks, and failure modes introduced by an indirect drive engine. Improvements in aircraft efficiency may include reduced weight, reduced risk of system failure, and improved overall aircraft fuel burn.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention 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 include 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.