Turbine engine including air turbine starter and bleed circuit

Abstract

A turbine engine includes an engine core, an engine driveshaft, an accessory gearbox (AGB), an air turbine starter (ATS), and a bleed air circuit. The engine core has a fan section, a compressor section, a combustion section, and a turbine section in a series flow arrangement. An engine drive shaft operably couples the fan section, the compressor section, and the turbine section. The AGB and the ATS are operably coupled to the engine drive shaft.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Patent Application No. 18 / 495,001, filed on October 26, 2023, now approved, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates generally to turbine engines including air turbine starters, and more particularly to a bleed air circuit from a turbine engine. Background Art

[0003] A turbine engine, such as a gas turbine engine, uses an air turbine starter (ATS) during startup of the turbine engine. The ATS is typically mounted near the turbine engine, and the ATS may be coupled to a source of high pressure fluid, such as compressed air, that impinges on a turbine rotor in the ATS, causing it to rotate at a relatively high rate. The ATS includes an output drive shaft, which is typically driven by the turbine rotor through a reduction gearbox, wherein the output drive shaft provides rotational energy to a rotatable element (e.g., a crankshaft or rotatable shaft) of the turbine engine to initiate rotation. The rotation caused by the ATS continues until the turbine engine reaches a self-sustaining operating speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A complete and enabling disclosure of the subject matter, including the best mode thereof, is set forth in this specification, which refers to the accompanying drawings, in which:

[0005] Figure 1 is a schematic diagram of a turbine engine with an air turbine starter according to various aspects described herein.

[0006] Figure 2 Is suitable for Figure 1 Schematic block diagram of a bleed air circuit used in a turbine engine of the invention, the bleed air circuit supplying bleed air from the turbine engine to a bleed air turbine of the turbine engine. DETAILED DESCRIPTION

[0007] Aspects of the present disclosure relate to a turbine engine including an ATS, a bleed air turbine (BAT), and a bleed air circuit for extracting bleed air from the turbine engine. The turbine engine includes an engine drive shaft. Both the BAT and the ATS are independently coupled to an accessory gearbox (AGB). The AGB is selectively coupled to the engine drive shaft. Both the drive of the ATS and the BAT can drive the engine drive shaft through the drive of the AGB.

[0008] The bleed air circuit is used to supply bleed air from the turbine engine to at least the BAT. The BAT is driven by the bleed air, which drives the AGB, and the AGB drives the engine drive shaft. A part of the bleed air in the bleed air circuit can be supplied to the system outside the turbine engine. The bleed air circuit including the BAT can be used to extract work from the bleed air to enhance the drive of the engine drive shaft. For ease of explanation, the present disclosure will be described with respect to the turbine engine. However, it will be understood that the disclosed aspects described herein are not limited thereto and can be generally applicable to other engines or other turbine engines. For example, the present disclosure can be applicable to an engine starter assembly used with any suitable engine or used in any suitable vehicle, and can be used to provide benefits in industrial, commercial and residential applications.

[0009] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, unless expressly identified otherwise, all embodiments described herein should be considered exemplary.

[0010] As used herein, terms such as “first,” “second,” and “third” may be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of each component.

[0011] The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle and are for the normal operating attitude of the gas turbine engine or vehicle. For example, for a gas turbine engine, front refers to a position closer to the engine inlet, while rear refers to a position closer to the engine nozzle or exhaust.

[0012] As used herein, the term "upstream" refers to the direction opposite to the direction of fluid flow, while the term "downstream" refers to the direction in the same direction as the direction of fluid flow. The terms "front" or "forward" mean in front of something, while "rear" or "rearward" mean behind something. For example, when used with respect to fluid flow, front / forward may mean upstream, while rear / rearward may mean downstream.

[0013] Furthermore, as used herein, the terms "radial" or "radially" refer to directions extending toward or away from a common center. For example, in the general context of turbine engines, radial refers to directions along a ray extending between a central longitudinal axis of the turbine engine and an outer engine circumference. Furthermore, as used herein, the terms "group" or "grouped" elements may be any number of elements, including only one.

[0014] All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, rear, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, front, rear, etc.) are used only for identification purposes to help the reader understand the present disclosure and do not cause limitations, particularly with respect to the position, orientation, or use of the disclosed aspects described herein. Connection references (e.g., attachment, coupling, fastening, connection, and connection) should be interpreted broadly and, unless otherwise indicated, may include intermediate structural elements between sets of elements and relative motion between elements. Therefore, a connection reference does not necessarily mean that two elements are directly connected and fixed to each other. The exemplary drawings are for illustrative purposes only, and the dimensions, positions, orders, and relative sizes reflected in the figures attached herein may vary.

[0015] As used herein, a "controller" may include at least one processor and memory. Non-limiting examples of memory may include random access memory (RAM), read-only memory (ROM), flash memory, or one or more different types of portable electronic memory, such as optical disks, DVDs, CD-ROMs, etc., or any suitable combination of these types of memory. The processor may be configured to run any suitable program or executable instructions designed to perform various methods, functions, processing tasks, calculations, etc., to enable or implement the technical operations or operations described herein. The program may include a computer program product, which may include a machine-readable medium for carrying or storing machine-executable instructions or data structures thereon. Such a machine-readable medium may be any available medium that can be accessed by a general or special-purpose computer or other machine with a processor. In general, such a computer program may include routines, programs, objects, components, data structures, algorithms, etc., which have the technical effect of performing a specific task or realizing a specific abstract data type.

[0016] The exemplary drawings are for illustration purposes only, and the dimensions, positions, orders, and relative sizes reflected in the drawings attached hereto may vary.

[0017] Figure 1 is a schematic perspective view of a turbine engine 14. The turbine engine 14 may include an air turbine starter (ATS) 10 and a bleed air turbine (BAT) 46. The ATS 10 is coupled to an accessory gearbox (AGB) 12, also referred to as a transmission housing. The BAT 46 is coupled to the AGB 12. The AGB 12 includes a housing (not shown) having at least a plurality of gears (not shown) disposed therein.

[0018] The turbine engine 14 may include a fan section 16, a compressor section 18, a combustion section 20, a turbine section 22, and an exhaust section 26 arranged in series flow. The fan section 16 may be at least partially enclosed by a fan case 28, or otherwise enclosed by a nacelle or casing of the turbine engine 14. The turbine engine 14 may include other components not shown.

[0019] The AGB 12, ATS 10, and BAT 46 are schematically shown mounted to respective portions of the turbine engine 14. At least a portion of the ATS 10, BAT 46, or AGB 12 may be located radially outward of the fan case 28. That is, the ATS 10, BAT 46, AGB 12, or a combination thereof may be located radially outward of the fan section 16. Alternatively, it is contemplated that in various and non-limiting examples, at least a portion of the ATS 10, BAT 46, AGB 12, or a combination thereof may be located within any suitable portion of the turbine engine 14, such as near the compressor section 18, wherein the ATS 10, BAT 46, or AGB 12 may be coupled to a transmission gearbox (not shown).

[0020] The AGB 12 may be coupled to the turbine engine 14 at a portion of the turbine section 22 via a mechanical power take-off 27. The mechanical power take-off 27 includes a plurality of gears and means for mechanically coupling the AGB 12 to the turbine engine 14.

[0021] Figure 2 are interconnected Figure 1 1 is a schematic block diagram of a turbine engine 14 and a bleed air circuit 30 of an ATS 10 .

[0022] The fan section 16, the compressor section 18, the combustion section 20, and the turbine section 22 collectively define the engine core 15. At least a portion of the engine core 15 may be disposed in a housing coupled to a fan case 28 ( Figure 1 ) or in an engine casing 17 of a nacelle. Any suitable portion of the turbine engine 14 may be disposed in the engine casing 17.

[0023] The compressor section 18 may include a low pressure (LP) compressor 34 and a high pressure (HP) compressor 36 in a series flow arrangement. The turbine section 22 may include a high pressure (HP) turbine 40 and a low pressure (LP) turbine 42 in a series flow arrangement. The combustion section 20 may include a combustor 38 disposed between the HP compressor 36 and the HP turbine 40 and fluidly coupling the HP compressor 36 to the HP turbine 40. An engine drive shaft 44 drivingly couples the turbine section 22 to the compressor section 18 and the fan section 16. Although not shown, the engine drive shaft 44 may include: a high pressure (HP) shaft drivingly coupling the HP turbine 40 to the HP compressor 36 to jointly define an HP spool; and a low pressure (LP) shaft drivingly coupling the LP turbine 42 to the LP compressor 34 and the fan section 16 to jointly define an LP spool.

[0024] The BAT 46 includes a BAT output shaft 48 and a BAT turbine 116 drivingly coupled to the BAT output shaft 48. The BAT output shaft 48 is drivingly coupled to the AGB 12.

[0025] The ATS 10 includes an ATS output shaft 50, an ATS gearbox 112, an ATS drive shaft 118, and an ATS turbine 114. The ATS turbine 114 is drivingly coupled to the ATS gearbox 112 via the ATS drive shaft 118 to define a mechanical input to the ATS gearbox 112. The ATS gearbox 112 is coupled to the ATS output shaft 50 to define a mechanical output of the ATS gearbox 112 and the ATS 10 as a whole. At least a portion of the ATS turbine 114, the ATS gearbox 112, the ATS drive shaft 118, and the ATS output shaft 50 may be received in an ATS housing (not shown). Both the BAT output shaft 48 and the ATS output shaft 50 define a mechanical input to the AGB 12.

[0026] The BAT 46 may be similar to the ATS 10 in that both the ATS 10 and the BAT include respective turbines (e.g., the ATS turbine 114 and the BAT turbine 116, respectively) and respective output drive shafts (e.g., the ATS output shaft 50 and the BAT output shaft 48, respectively). However, the BAT 46 may be formed without a respective gearbox and may be coupled to the AGB 12 via the BAT output shaft 48, whereas the ATS 10 includes the ATS gearbox 112 and may include the ATS output shaft 50 that may be selectively coupled to the AGB 12 via a clutch or a decoupler. Alternatively, the BAT 46 may include a gearbox. Since the BAT output shaft 48 is coupled to the AGB 12, any rotation of the BAT turbine 116 (e.g., by supplying bleed air to the BAT 46) will cause energy to be transmitted from the BAT 46 to the AGB 12 via the BAT output shaft 48. Because the ATS 10 includes a decoupler or clutch, rotation of the ATS turbine 114 does not mean that energy will be transferred from the ATS 10 to the AGB 12 via the ATS output shaft 50 unless the clutch or decoupler of the ATS 10 is intentionally engaged.

[0027] The AGB 12 is operably coupled to the engine drive shaft 44. As shown, the AGB 12 is indirectly operably coupled to the engine drive shaft 44. The AGB 12 includes an AGB drive shaft 52 that defines a mechanical output of the AGB 12. The AGB drive shaft 52 is selectively operably coupled to the engine drive shaft 44. As a non-limiting example, a decoupler 54 may selectively operably couple the AGB drive shaft 52 and the engine drive shaft 44. Alternatively, the AGB drive shaft 52 may be directly coupled to the engine drive shaft 44 or integrally formed with the engine drive shaft 44. The AGB 12 may be operably coupled to any suitable portion of the engine drive shaft 44.

[0028] The turbine engine 14 includes a precooler heat exchanger (PCE) 78 configured to direct bleed air from the turbine engine 14 to an external system 86 disposed outside of the turbine engine 14. The PCE 78 is fluidly coupled to the external system 86 via a bleed air outlet line 70. The external system 86 may include any suitable system that utilizes bleed air from the turbine engine 14 during operation of the external system 86, such as, but not limited to, an environmental control system (ECS). The PCE 78 is also fluidly coupled to a cooling fluid source via a cooling fluid input 80. The cooling fluid source may be a portion of the turbine engine 14, such as a fan section 16 or a compressor section 18. The PCE 78 may discharge cooling fluid received from the cooling fluid source via a cooling fluid output 82. The cooling fluid output 82 may be fluidly coupled to the atmosphere or a portion of the turbine engine 14, such as a turbine section 22, an exhaust section 26 ( Figure 1) or a combination thereof.

[0029] The bleed air circuit 30 is fluidly coupled to the turbine engine 14 and is configured to extract bleed air from at least a portion of the turbine engine 14. The bleed air circuit 30 may include two bleed air passages that are directly fluidly coupled to corresponding portions of the turbine engine. It will be appreciated that the passages of the bleed air circuit 30 may be formed as discrete elements (e.g., ducts), or otherwise integrally formed within an existing structure such as the turbine engine 14. As a non-limiting example, the bleed air circuit 30 may include an LP bleed air passage 56 and an HP bleed air passage 58. The HP bleed air passage 58 may be coupled to a portion of the turbine engine 14 that has a higher pressure working airflow relative to a position where the LP bleed air passage 56 is disposed. In other words, the HP bleed air passage 58 includes bleed air having a higher pressure than the bleed air of the LP bleed air passage 56. As a non-limiting example, the LP bleed air passage 56 may be directly fluidly coupled to the LP compressor 34, and the HP bleed air passage 58 may be directly fluidly coupled to the HP compressor 36.

[0030] The bleed air circuit 30 includes a first bleed air passage 60, a second bleed air passage 62, and a third bleed air passage 64. The first bleed air passage 60 is fluidly coupled to the turbine engine 14 through the LP bleed air passage 56 and the HP bleed air passage 58. The second bleed air passage 62 fluidly couples the first bleed air passage 60 to the BAT 46 and defines a fluid input of the BAT 46. The third bleed air passage 64 fluidly couples the BAT 46 to a bleed air inlet 68 that leads directly to the PCE 78.

[0031] The bleed air circuit 30 includes a bypass passage 66 that fluidly couples the first bleed air passage 60 to the third bleed air passage 64 while bypassing the BAT 46 or the second bleed air passage 62. The bypass passage 66 and the third bleed air passage 64 meet at a junction 88. The junction 88 may be disposed upstream of the PCE 78. Alternatively, the bypass passage 66 and the third bleed air passage 64 may be individually and separately coupled to the PCE 78 such that the bypass passage 66 bypasses the BAT 46, and the bypass passage 66 and the third bleed air passage 64 together define a bleed air inlet line 68 leading to the PCE 78. In the case where the bypass passage 66 and the third bleed air passage 64 are independently coupled to the PCE 78, the PCE 78 defines the junction 88. Since the PCE 78 is output to the external system 86 through the bleed air outlet line 70 , the third bleed air passage 64 can be said to fluidly couple the BAT 46 to the external system 86 , and the bypass passage 66 can be said to fluidly couple the first bleed air passage 60 to the external system 86 .

[0032] The bleed air circuit 30 includes a fourth bleed air passage 72 that defines a fluid input of the ATS 10. The fourth bleed air passage 72 may be fluidly coupled to any suitable portion of the bleed air circuit 30. As a non-limiting example, the fourth bleed air passage 72 may be fluidly coupled to a bleed air outlet line 70. The ATS 10 may discharge the fluid received from the fourth bleed air passage 72 via an exhaust line 84. The exhaust line 84 may be fluidly coupled to the atmosphere or a portion of the turbine engine 14, such as a fan section 16, a compressor section 18, a turbine section 22, an exhaust section 26, or a combination thereof of the turbine engine 14.

[0033] Bleed air circuit 30 may include an auxiliary bleed air passage 74 that is fluidly coupled to an auxiliary system 76 of turbine engine 14. Auxiliary system 76 is defined as any suitable system of turbine engine 14 that may utilize bleed air from at least one of HP bleed air passage 58 or LP bleed air passage 56. As non-limiting examples, auxiliary system 76 may include an oil cooling system, a wing anti-ice system, a blade anti-ice system, a nacelle anti-ice system, or a combination thereof.

[0034] At least a portion of the bleed air circuit 30, the ATS 10, the AGB 12, and the BAT 46 are disposed outside the engine housing 17. As a non-limiting example, the bleed air circuit 30 (except for the LP bleed air passage 56 and the HP bleed air passage 58), the ATS 10, the AGB 12, and the BAT 46 are all disposed outside the engine housing 17.

[0035] The bleed air circuit 30 is selectively fluidly coupled to the LP bleed air passage 56 and the HP bleed air passage 58 by a first valve 90 and a second valve 92, respectively. The first valve 90 and the second valve 92 may include any suitable valves. As a non-limiting example, the first valve 90 may include a check valve so that during operation of the turbine engine 14, bleed air is supplied through the LP bleed air passage 56. As a non-limiting example, the first valve 90 may include a switch valve so that during operation of the turbine engine 14, bleed air is selectively supplied through the LP bleed air passage 56. As a non-limiting example, the second valve 92 may include a switch valve or a stop valve that selectively opens and closes to supply bleed air from the HP bleed air passage 58 to the bleed air circuit 30 or to stop bleed air from the HP bleed air passage 58 from flowing into the bleed air circuit 30, respectively. As a non-limiting example, the second valve 92 may include a check valve so that during operation of the turbine engine 14, bleed air is supplied through the HP bleed air passage 58.

[0036] The induction circuit 30 includes a third valve 94 arranged along the first induction passage 60. The third valve 94 may include any suitable valve. As a non-limiting example, the third valve 94 may include a check valve arranged along the junction between the first induction passage 60 and the second induction passage 62, which prevents backflow from the second induction passage 62 or the bypass passage 66 to the first induction passage 60. As a non-limiting example, the third valve 94 may include a diverter valve, which transfers all fluids below a specific volume flow rate to the second induction passage 62, and transfers all fluids above a specific volume flow rate to the bypass passage 66. The diverter valve may be used for situations where the BAT 46 has a specific maximum volume flow rate that it can accept. In this case, the diverter valve may be dimensioned to ensure that the volume flow rate of the fluid in the second induction passage 62 and supplied to the BAT 46 does not exceed the maximum volume flow rate of the BAT 46. The third valve 94 may be arranged at the junction between the first induction passage 60, the second induction passage 62 and the bypass passage 66.

[0037] The induction air circuit 30 includes a fourth valve 96 disposed along the second induction air passage 62. The fourth valve 96 fluidly couples the first induction air passage 60 to the BAT 46. The fourth valve 96 may include any suitable valve. As a non-limiting example, the fourth valve 96 may include a needle valve for controlling the volume flow rate of the fluid supplied to the BAT 46 within the second induction air passage 62.

[0038] The bleed air circuit 30 may include a fifth valve 98 disposed along the bleed air inlet line 68. The fifth valve 98 fluidly couples the bleed air inlet line 68 to the PCE 78 or otherwise to the external system 86. The fifth valve 98 may include any suitable valve. As a non-limiting example, the fifth valve 98 may include an on-off valve or a shutoff valve.

[0039] The bleed air circuit 30 may include a sixth valve 100 disposed along the fourth bleed air passage 72. The sixth valve 100 fluidly couples the bleed air outlet line 70 to the ATS 10. The sixth valve 100 may include any suitable valve. As a non-limiting example, the sixth valve 100 may include a switch valve or a stop valve.

[0040] The induction air circuit 30 may include a seventh valve 102 disposed along the auxiliary induction air passage 74. The seventh valve 102 fluidically couples the first induction air passage 60 to the auxiliary induction air passage 74. The seventh valve 102 may include any suitable valve. As a non-limiting example, the seventh valve 102 may include a switch valve or a stop valve.

[0041] It will be appreciated that the valves of the bleed air circuit 30 may be changed, moved, or removed based on the needs of the bleed air circuit 30. The turbine engine 14 may include any other suitable valves, such as, but not limited to, an eighth valve 104 disposed along the cooling fluid input 80. The eighth valve 104 may fluidly couple the cooling fluid within the cooling fluid input 80 to the PCE 78. As a non-limiting example, the bleed air circuit 30 may include any suitable components along the respective passages of the bleed air circuit 30, configured to generate a pressure drop along the respective passages. As a non-limiting example, the bypass passage 66 may include an orifice plate to ensure that the fluid within the bypass passage 66 is at a desired pressure before being supplied to the PCE 78, the external system 86, the confluence 88, or a combination thereof. The components configured to generate a pressure drop along the respective passages may be any suitable components, such as, but not limited to, an orifice plate, a valve, an ejector, a hole, or a combination thereof.

[0042] It will be appreciated that components of the bleed air circuit 30 or the turbine engine 14 may be moved, replaced, or removed relative to the illustrated configuration. For example, the PCE 78 may be excluded from the turbine engine 14 or otherwise moved to a different location along the bleed air circuit 30. As a non-limiting example, the fourth bleed air passage 72 may be disposed upstream of the PCE 78. As a non-limiting example, the bleed air circuit 30 may include additional or different locations of bleed air passages configured to extract bleed air from the turbine engine 14, including but not limited to the fan section 16, the compressor section 18, the turbine section 22, the exhaust section 26, or a combination thereof.

[0043] A controller 106 (e.g., an electronic controller) may be used to selectively and operably control certain portions of the turbine engine 14. As a non-limiting example, the controller 106 may be used to selectively and operably control the first valve 90, the second valve 92, the third valve 94, the fourth valve 96, the fifth valve 98, the sixth valve 100, the seventh valve 102, the eighth valve 104, the separator 54, any other valve, or any combination thereof. The controller 106 may include a processor 108 and a memory 110, and may be communicatively coupled to the bleed air circuit 30 or a corresponding portion of the turbine engine 14. The memory 110 may be defined as a memory of instructions and codes for controlling or monitoring various aspects of the bleed air circuit 30 or the turbine engine 14. For example, the memory 110 may store code, executable instructions, commands, instructions, authorization keys, dedicated data keys, passwords, etc. The memory 110 may be RAM, ROM, flash memory, or one or more different types of portable electronic memory, such as an optical disk, DVD, CD-ROM, etc., or any suitable combination of these types of memory. The processor 108 may be defined as a portion of the controller 106 that may receive input, perform calculations, and output executable data. The processor 108 may include a microprocessor. Although described with respect to the controller 106, it will be understood that the controller 106 may be a control system that includes a plurality of separate controllers coupled to respective portions of the turbine engine 14. The control system may collectively define a system for automatically controlling the operation of the turbine engine 14 and the bleed air circuit 30.

[0044] During operation of the turbine engine 14, the free stream airflow flows against the front of the turbine engine 14. A portion of the free stream airflow enters the fan section 16 to define an inlet airflow. A portion of the inlet airflow enters the engine core 15 to define a working airflow, which is used for combustion within the engine core 15.

[0045] More specifically, the working airflow flows into the LP compressor 34, which then pressurizes the working airflow, thereby defining a pressurized airflow, which is supplied to the HP compressor 36, which further pressurizes the air. The working airflow or pressurized airflow from the HP compressor 36 is mixed with fuel and ignited in the combustor 38, thereby producing combustion gases. The HP turbine 40 extracts some work from these gases, and the HP turbine 40 drives the HP compressor 36 through the engine drive shaft 44. The combustion gases are discharged into the LP turbine 42, which extracts additional work to drive the LP compressor 34, and the working airflow or exhaust gas is ultimately discharged from the turbine engine 14 via the exhaust section 26. The drive of the LP turbine 42 drives the engine drive shaft 44 to rotate the fan section 16 and the LP compressor 34.

[0046] It is contemplated that a portion of the working airflow is extracted as bleed air (e.g., from the compressor section 18). The bleed air provides airflow for engine components that require cooling. The temperature of the working airflow leaving the combustion section 20 is significantly elevated relative to the working airflow within the compressor section 18. Therefore, the cooling provided by the bleed air is necessary for operating such engine components in a high temperature environment or hot section of the un-bypassed turbine engine 14.

[0047] During operation, bleed air from a cold section (e.g., the compressor section 18 or the fan section 16) may be selectively extracted into the bleed air circuit 30 through, for example, the LP bleed air passage 56 and the HP bleed air passage 58. Since the bleed air circuit 30 may include at least two bleed air passages (e.g., the LP bleed air passage 56 and the HP bleed air passage 58), bleed air from at least one location within the turbine engine 14 may be supplied to the bleed air circuit 30. As non-limiting examples, bleed air only from the LP compressor 34, only from the HP compressor 36, or a combination thereof may be supplied to the bleed air circuit 30. The fluid provided to the bleed air circuit 30 through at least one of the LP bleed air passage 56, the HP bleed air passage 58, or any other bleed air passage directly fluidly coupled to the turbine engine 14 will hereinafter be referred to as circuit bleed air.

[0048] Then, the circuit bleed air from at least one of the LP bleed air passage 56, the HP bleed air passage 58, or any other bleed air passage directly fluidly coupled to the turbine engine 14 is supplied to the first bleed air passage 60. Then, depending on the operation of the third valve 94, the fourth valve 96, and the seventh valve 102, the circuit bleed air in the first bleed air passage 60 may be supplied to at least one of the second bleed air passage 62, the bypass passage 66, or the auxiliary bleed air passage 74. As a non-limiting example, if it is determined that the operation of the turbine engine 14 desires the operation of the auxiliary system 76 or for other reasons (e.g., wing anti-icing of an aircraft to which the turbine engine is coupled), the seventh valve 102 may be selectively opened via the controller 106 so that at least a portion of the circuit bleed air is supplied to the auxiliary system 76.

[0049] The circuit bleed air can be selectively supplied to the BAT 46 through the second bleed air passage 62. The circuit bleed air supplied to the BAT 46 drives the BAT turbine, which thereby drives the BAT output shaft 48. The BAT output shaft 48 can be coupled to or selectively coupled to (e.g., through a clutch, not shown) the AGB 12, so that the BAT output shaft 48 can drive the AGB 12. The drive of the AGB 12 will drive the AGB drive shaft 52, which can ultimately drive the engine drive shaft 44. Therefore, it will be understood that the supply of circuit bleed air to the BAT 46 can be used to drive the engine drive shaft 44. The circuit bleed air can be supplied to the ATS 10 through the fourth bleed air passage 72 to drive the ATS turbine 114, which drives the ATS output shaft 50. The ATS output shaft 50 is coupled to or selectively coupled to (e.g., through a clutch, not shown) the AGB 12. The drive of the AGB 12 will drive the AGB drive shaft 52, which can drive the engine drive shaft 44.

[0050] Driving the engine drive shaft 44 by supplying the circuit bleed air to the BAT 46 may be used to enhance at least one of the rotational speed or torque of the engine drive shaft 44. In other words, during normal operation of the turbine engine 14, the engine drive shaft 44 may be driven by the turbine section 22. The BAT 46 may be used to recover energy from the bleed air to enhance the driving of the engine drive shaft 44, such that during operation of the turbine engine 14, the engine drive shaft 44 is partially driven by the turbine section 22 and the BAT 46. It is contemplated that the circuit bleed air may be supplied or selectively supplied to the BAT 46 to enhance the driving of the engine drive shaft 44. As a non-limiting example, if at least one of the sensed torque or rotational speed of the engine drive shaft 44 is lower than the desired torque or rotational speed of the engine drive shaft 44, the circuit bleed air may be selectively supplied to the BAT 46 to ultimately increase at least one of the torque or rotational speed of the engine drive shaft 44, such as to the desired torque or rotational speed. It is contemplated that the BAT 46 may also be used as a brake for the engine drive shaft 44. As a non-limiting example, the BAT 46 may rotate the BAT output shaft 48 or otherwise rotate the AGB drive shaft 52 in an opposite manner to the rotation of the engine drive shaft 44. Thus, the BAT 46 may be used to counteract or otherwise slow the rotation of the engine drive shaft 44.

[0051] The drive of the engine drive shaft 44 by the ATS10 can be used for one or both of the start-up or restart of the turbine engine 14. During the startup, air can be supplied to the ATS10 through the bleed air circuit 30 or from an external source (e.g., a ground cart) to drive the engine drive shaft 44 to start the process of sucking air through the fan section 16 to start the process of compressing and burning the working airflow. During the restart (e.g., when the turbine engine 14 has been started before but has stopped continuing to operate), the engine drive shaft 44 may begin to slow down, so that the speed of the engine drive shaft 44 is reduced, but air is still sucked in to limit the working airflow and bleed air. The circuit bleed air can be supplied to the ATS10 through the bleed air circuit 30. The ATS10 can then increase the speed of the engine drive shaft 44 so that the turbine engine 14 can continue to suck the working airflow, and then try to restart the turbine engine 14 by burning the compressed airflow.

[0052] It is contemplated that the engine drive shaft 44 may include a first demand to transfer energy from the ATS 10 in order to start or restart the turbine engine 14. It is contemplated that the engine drive shaft may have a second demand to transfer energy from the BAT 46 during normal operation of the turbine engine 14. The second demand is less than the first demand because the BAT 46 is used when the engine drive shaft 44 is already rotating due to the operation of the turbine engine 14, and the ATS 10 is used when the engine drive shaft 44 is slowed or not moving. Therefore, the ATS 10 requires the use of an ATS gearbox 112 to ensure that the output of the ATS 10 through the ATS output shaft 50 is at a level sufficient to meet the first demand. Since the second demand is less than the first demand, the BAT 46 does not need to use a corresponding gearbox to ensure that the output of the BAT 46 through the BAT output shaft 48 is at a level sufficient to meet the second demand. In addition, since the ATS 10 includes the ATS gearbox 112, it may be necessary to decouple the ATS 10 from the AGB 12, or otherwise ensure that bleed air is not supplied to the ATS 10 during normal operation of the turbine engine 14 to ensure that the second demand is not exceeded. Therefore, it has been found to be advantageous to include a separate turbine (eg, BAT 46 ) that may be used during normal operation of turbine engine 14 to ensure that the second demand is not exceeded.

[0053] The circuit bleed air supplied to the BAT 46 may then expand as it flows through the BAT turbine of the BAT 46. The expansion of the circuit bleed air causes the pressure and temperature of the circuit bleed air to decrease. The third bleed air passage 64 defines a fluid outlet of the BAT 46. Thus, the pressure and temperature of the circuit bleed air supplied to the BAT 46 (via the second bleed air passage 62) are higher than the pressure and temperature of the circuit bleed air supplied from the BAT 46 (via the third bleed air passage 64).

[0054] Subsequently, the circuit bleed air in the third bleed air passage 64 may be selectively supplied to the PCE 78 to at least partially define a bleed air inlet line 68 to the PCE 78. At least a portion of the circuit bleed air may be supplied to the PCE 78 via the bypass passage 66 to bypass the BAT 46. The amount of circuit bleed air supplied via the bypass passage 66 may depend on at least one of the volumetric flow rate of the circuit bleed air in the first bleed air passage 60 or the required pressure of the circuit bleed air supplied to the PCE 78 or the external system 86. As a non-limiting example, if the circuit bleed air in the third bleed air passage 64 is lower than the required pressure of the circuit bleed air supplied to the external system 86, the bypass passage 66 may supply circuit bleed air (with a higher pressure and temperature than the circuit bleed air in the third bleed air passage 64) from the first bleed air passage and mix with the circuit bleed air from the third bleed air passage 64 at the confluence 88. This in turn increases the temperature and pressure of the circuit bleed air supplied to the PCE 78 or the external system 86 relative to the circuit bleed air in the third bleed air passage 64.

[0055] When the circuit bleed air is cooled by flowing through the BAT 46, the cooling of the circuit bleed air by the PCE 78 can be reduced or eliminated. In other words, the PCE 78 does not need to cool the circuit bleed air as much as in the case where the circuit bleed air is not first cooled by flowing through the BAT 46. Pre-cooling the circuit bleed air before supplying it to the PCE 78 in turn reduces the required size of the PCE 78 and the required amount of cooling fluid supplied to the PCE 78 through the cooling fluid input 80. The amount of circuit bleed air supplied and cooled by the BAT 46 can be large enough so that the circuit bleed air in the third bleed air passage 64 is at a sufficiently low temperature that it does not need to be further cooled by the PCE 78 before being supplied to the external system 86. This in turn means that the PCE 78 can be eliminated or completely bypassed. The amount of cooling fluid supplied to the PCE 78 can be reduced, which means that less air needs to be exhausted from the turbine engine 14 or otherwise obtained from other locations of the turbine engine 14 (e.g., through the RAM air configuration) to form the cooling fluid. This in turn means more air is available for compression and combustion, thereby increasing the speed and torque of the engine drive shaft 44. The circuit bleed air in the bleed air circuit 30 may ultimately be supplied to the external system 86 where it is used to operate the external system 86.

[0056] By using the controller 106, the operation of the BAT 46 and the ATS 10 can be automatically completed. As a non-limiting example, the controller 106 can operate the BAT 46 by supplying circuit bleed air to the BAT 46 so as to enhance the power of the engine drive shaft 44 based on the measured torque or speed of the engine drive shaft 44 and the required output of the turbine engine 14. As a non-limiting example, the controller 106 can include in the memory 110 or otherwise in a memory accessible to the controller 106 a function that anticipates the use of the BAT 46 to enhance the power of the engine drive shaft 44 during normal operation of the turbine engine 14. In other words, the turbine engine 14 can be operated in such a manner that the BAT 46 is expected to be used during normal operation of the turbine engine 14. Therefore, the BAT 46 can be used to enhance the power of the engine drive shaft 44, even if the turbine engine 14 is capable of producing the required output without the use of the BAT 46. This in turn allows the turbine engine 14 to operate more efficiently because the turbine engine 14 can extract additional work from the bleed air to enhance the power of the engine drive shaft 44 , thereby reducing the amount of gas fuel required to produce the combustion gases needed to drive the engine drive shaft 44 .

[0057] Benefits associated with the present disclosure include a turbine engine with higher efficiency than a conventional turbine engine. For example, a conventional turbine engine may include a bleed air circuit that supplies bleed air to an external system. However, work is not extracted from the bleed air to drive the engine drive shaft. However, a turbine engine as described herein includes a bleed air circuit with a BAT that extracts work from the bleed air before the bleed air is supplied to the external system. The extracted work is in turn used to enhance the drive of the engine drive shaft. In other words, compared to a conventional turbine engine, extracting work from the bleed air in turn improves the efficiency of the turbine engine.

[0058] Other advantages of the present disclosure include reducing the footprint or eliminating the PCE. For example, a conventional turbine engine including a bleed air circuit for supplying bleed air to an external system requires a PCE to cool the bleed air to the temperature required by the external system. However, a bleed air circuit as described herein can pre-cool the bleed air via a BAT. Pre-cooling of the bleed air can in turn reduce the size of the PCE or otherwise completely eliminate the need for a PCE compared to a conventional bleed air circuit.

[0059] Other advantages of the present disclosure include a bleed air circuit that can both enhance the drive of the engine drive shaft and enable at least one of starting or restarting the turbine engine. As described herein, the bleed air circuit includes a BAT and an ATS so that bleed air from the turbine engine can be used to enhance the drive of the engine drive shaft or restart the turbine engine while still supplying bleed air to auxiliary systems or external systems.

[0060] Compared with conventional turbine engines, the additional advantages of the present disclosure include an increase in the amount of bleed air extracted from the turbine engine. For example, in conventional turbine engines, the bleed air extracted is not used to enhance the power of the engine drive shaft. If too much bleed air is extracted from the turbine engine, enough combustion gases will not be produced, or the combustion gases will not reach the required pressure. This in turn can cause the conventional turbine engine to stall. However, as described herein, the turbine engine uses bleed air to enhance the power of the engine drive shaft (e.g., by BAT), which in turn means that more bleed air can be extracted from the turbine engine without worrying about the turbine engine stalling. Since more bleed air can be extracted from the turbine engine compared with conventional turbine engines, more bleed air can be supplied to auxiliary systems or external systems, thereby improving the efficiency of the system to which the bleed air is supplied.

[0061] To the extent not already described, the different features and structures of each aspect may be used in combination or in place of one another as desired. The fact that a feature is not shown in all examples does not mean that it cannot be shown in this way, but rather that it is done so for the sake of brevity of description. Thus, the various features of different aspects may be mixed and matched as desired to form new aspects, whether or not the new aspects are explicitly described. All combinations or permutations of the features described herein are encompassed in the present disclosure.

[0062] This written description uses examples to describe the disclosed aspects described herein, including the best mode, and also to enable those skilled in the art to practice the disclosed aspects, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosed aspects 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 language of the claims.

[0063] Further aspects are provided by the subject matter of the following clauses:

[0064] A turbine engine comprises: an engine core including a fan section, a compressor section, a combustion section and a turbine section arranged in a series flow; an engine drive shaft operably connecting the fan section, the compressor section and the turbine section; an accessory gearbox (AGB) operably connecting to the engine drive shaft; an air turbine starter (ATS) having an ATS turbine, an ATS gearbox, an ATS drive shaft operably connecting the ATS turbine and the ATS gearbox, and an ATS output shaft operably connecting the ATS gearbox to the AGB; a bleed air turbine (BAT) including a BAT turbine and a BAT output shaft operably connecting to the AGB; and a bleed air circuit including a first bleed air passage fluidly connecting to the compressor section, a second bleed air passage fluidly connecting the first bleed air passage to an input of the BAT, a third bleed air passage fluidly connecting to an output of the BAT, and a bypass passage fluidly connecting to the third bleed air passage while bypassing the BAT.

[0065] A component for a turbine engine, the component comprising: an accessory gearbox (AGB); an air turbine starter (ATS) having an ATS turbine, an ATS gearbox, an ATS drive shaft operably coupling the ATS turbine and the ATS gearbox, and an ATS output shaft operably coupling the ATS gearbox to the AGB; a bleed air turbine (BAT) comprising a BAT turbine and a BAT output shaft operably coupled to the AGB; and a bleed air circuit comprising a first bleed air passage, a second bleed air passage fluidly coupling the first bleed air passage to an input of the BAT, a third bleed air passage fluidly coupled to an output of the BAT, and a bypass passage fluidly coupled to the third bleed air passage while bypassing the BAT.

[0066] A turbine engine as claimed in any preceding clause, wherein driving the BAT by means of working fluid supplied to the BAT via the second bleed air passage drives the AGB via the BAT output shaft.

[0067] Turbine engine according to any preceding clause, wherein the AGB is driven by the BAT output shaft during operation of the turbine engine.

[0068] A turbine engine according to any preceding clause, wherein the BAT turbine is directly coupled to the AGB via a BAT output shaft.

[0069] The turbine engine according to any preceding clause, further comprising a precooler heat exchanger (PCE) fluidly coupled to the fan section and to a system external to the turbine engine.

[0070] A turbine engine as claimed in any preceding clause, wherein the third bleed air passage fluidly couples the BAT to the PCE and the bypass passage fluidly couples the first bleed air passage to the PCE.

[0071] A turbine engine as claimed in any preceding clause, wherein the third bleed air passage and the bypass passage meet at a confluence upstream of the PCE.

[0072] A turbine engine as in any preceding clause, wherein the PCE is selectively fluidly coupled to at least one of the third bleed air passage or the bypass passage to define a fluid input to the PCE, and to a system external to the turbine engine to define a fluid output of the PCE.

[0073] A turbine engine as in any preceding clause, wherein the PCE comprises a cooling fluid input and a cooling fluid output, wherein the cooling fluid input is fluidly coupled to at least one of the fan section or the compressor section.

[0074] A turbine engine as claimed in any preceding clause, wherein the system external to the turbine engine comprises an environmental control system.

[0075] A turbine engine according to any preceding clause, wherein the second and third bleed air passages each comprise a respective working fluid having a respective temperature and a respective pressure, and the temperature and pressure of the working fluid in the second bleed air passage are higher than the temperature and pressure of the working fluid in the third bleed air passage.

[0076] A turbine engine according to any preceding clause, wherein the ATS is configured to restart the turbine engine during deceleration of the turbine engine and by driving of the ATS output shaft.

[0077] A turbine engine according to any preceding clause, wherein the bleed air circuit comprises a fourth bleed air passage fluidly coupling at least one of the third bleed air passage or the bypass passage to the ATS, and wherein the working fluid within the fourth bleed air passage is supplied to the ATS during restart of the turbine engine.

[0078] A turbine engine according to any preceding clause, wherein the bleed air circuit comprises a low pressure (LP) bleed air passage and a high pressure (HP) bleed air passage, wherein the LP bleed air passage is fluidly coupled to a portion of the turbine engine upstream of the HP bleed air passage.

[0079] A turbine engine as claimed in any preceding clause, wherein the LP bleed air passage and the HP bleed air passage are each independently, selectively fluidly coupled to the first bleed air passage.

[0080] A turbine engine according to any preceding clause, wherein the compressor section comprises a high pressure (HP) compressor and a low pressure (LP) compressor, the LP bleed air passage being fluidly coupled to the LP compressor and the HP bleed air passage being fluidly coupled to the HP compressor.

[0081] A turbine engine according to any preceding clause, further comprising a controller configured to automatically and selectively supply working fluid in the second bleed air passage to at least one of the BAT or the bypass passage based on at least one of a rotational speed or torque of the engine drive shaft or a requirement of a system external to the turbine engine.

[0082] A turbine engine as claimed in any preceding clause, wherein the bleed air circuit further comprises an auxiliary system bleed air passage fluidly coupling the first bleed air passage to an auxiliary system.

[0083] A turbine engine according to any preceding clause, further comprising an engine casing housing an engine core, wherein the BAT and the ATS are arranged outside the engine casing.

[0084] A turbine engine according to any preceding clause, wherein drive of both the ATS and the BAT drives the engine drive shaft via the AGB.

[0085] A turbine engine according to any preceding clause, further comprising a first valve disposed along the LP bleed air passage and selectively fluidly coupling bleed air from the turbine engine to the LP bleed air passage.

[0086] A turbine engine according to any preceding clause, further comprising a second valve disposed along the HP bleed air passage and selectively fluidly coupling bleed air from the turbine engine to the HP bleed air passage.

[0087] A turbine engine according to any preceding clause, further comprising a third valve disposed along the first bleed air passage, the third valve selectively coupling circuit bleed air from the first bleed air passage to the BAT.

[0088] A turbine engine as claimed in any preceding clause, wherein the third valve is provided at a junction between the first bleed air passages.

[0089] A turbine engine as claimed in any preceding clause, wherein the third valve selectively fluidly couples bleed air from the turbine engine to at least one of the bypass passage or the second bleed air passage.

[0090] A turbine engine according to any preceding clause, further comprising a fourth valve arranged along the second bleed air passage.

[0091] A turbine engine as claimed in any preceding clause, wherein the fourth valve selectively fluidly couples the circuit bleed air from the first bleed air passage to the BAT.

[0092] A turbine engine according to any preceding clause, further comprising a sixth valve selectively fluidly coupling at least one of the third bleed air passage or the bypass passage to the PCE or an external system.

[0093] A turbine engine as claimed in any preceding clause, wherein the sixth valve is arranged downstream of a junction between the bypass passage and the third bleed air passage.

[0094] A turbine engine as claimed in any preceding clause, wherein the sixth valve defines a junction between the bypass passage and the third bleed air passage.

[0095] A turbine engine according to any preceding clause, further comprising a seventh valve arranged along the fourth bleed air passage.

[0096] A turbine engine as in any preceding clause, wherein the fourth valve selectively fluidly couples circuit bleed air from at least one of the bypass passage or the third bleed air passage to the ATS.

[0097] A method of operating a turbine engine according to any preceding clause, the method comprising supplying bleed air from the turbine engine to a BAT.

[0098] A method according to any preceding clause, further comprising driving a BAT output shaft via bleed air supplied to the BAT.

[0099] A method according to any preceding clause, further comprising driving the engine drive shaft at least partially via the BAT output shaft.

[0100] A method according to any preceding clause, further comprising driving the engine drive shaft at least partially via the BAT output shaft during operation of the turbine engine.

[0101] A method according to any preceding clause, further comprising supplying bleed air from the turbine engine from a first location and a second location different from the first location and supplying the bleed air to the BAT.

[0102] The method of any preceding clause, further comprising supplying bleed air from the turbine engine and supplying the bleed air to the BAT from a first location, a second location different from the first location, and a third location different from the first location and the second location.

Claims

1. A turbine engine, comprising: an engine core including a fan section, a compressor section, a combustion section, a turbine section, and an engine drive shaft operably coupling the fan section, the compressor section, and the turbine section; an accessory gearbox (AGB) operatively coupled to the engine drive shaft; an air turbine starter (ATS) having an ATS turbine, an ATS gearbox, an ATS drive shaft operably coupling the ATS turbine and the ATS gearbox, and an ATS output shaft operably coupling the ATS gearbox to the AGB; a bleed air turbine BAT including a BAT turbine and a BAT output shaft operatively coupled to the AGB; as well as A bleed air circuit comprising: a first bleed air passage fluidly coupled to the compressor section; a second bleed air passage fluidly coupling the first bleed air passage to an input of the BAT; a third bleed air passage fluidly coupled to an output of the BAT; and A bypass passage is fluidly coupled to the third bleed air passage while bypassing the BAT.

2. The turbine engine according to claim 1, wherein: The AGB is driven via the BAT output shaft by driving the BAT through the working fluid supplied to the BAT via the second bleed air passage.

3. The turbine engine according to claim 2, wherein: The AGB is driven by the BAT output shaft during operation of the turbine engine.

4. The turbine engine according to claim 1, wherein: The BAT turbine is directly coupled to the AGB through the BAT output shaft. 5 . The turbine engine of claim 1 , further comprising a precooler heat exchanger (PCE) fluidly coupled to the fan section and to a system external to the turbine engine.

6. The turbine engine according to claim 5, wherein: The third induction passage fluidly couples the BAT to the PCE, and the bypass passage fluidly couples the first induction passage to the PCE.

7. The turbine engine according to claim 5, wherein: The third air induction passage and the bypass passage meet at a confluence portion upstream of the PCE.

8. The turbine engine according to claim 5, wherein: The PCE is selectively fluidly coupled to at least one of the third bleed air passage or the bypass passage to define a fluid input to the PCE and is fluidly coupled to a system external to the turbine engine to define a fluid output of the PCE.

9. The turbine engine according to claim 8, wherein: The PCE includes a cooling fluid input and a cooling fluid output, wherein the cooling fluid input is fluidly coupled to at least one of the fan section or the compressor section.

10. The turbine engine according to claim 5, wherein: Systems external to the turbine engine include an environmental control system.

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