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

Technical Field

[0001] 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

[0002] 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

[0003] 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:

[0004] Figure 1 is a schematic diagram of a turbine engine with an air turbine starter according to various aspects described herein.

[0005] Figure 2 Is suitable for Figure 1 Schematic block diagram of a bleed air circuit used in a turbine engine of FIG. 1 , which supplies bleed air from the turbine engine to an air turbine starter. DETAILED DESCRIPTION

[0006] Aspects of the present disclosure relate to a turbine engine including an ATS and a bleed air circuit for extracting bleed air from the turbine engine. The turbine engine includes an engine drive shaft. The ATS is coupled to an accessory gearbox (AGB). The AGB is selectively coupled to the engine drive shaft. The drive of the ATS can drive the engine drive shaft through the drive of the AGB.

[0007] The bleed air circuit is used to supply bleed air from the turbine engine to the ATS. The ATS is driven by the bleed air, which drives the AGB, and the AGB drives the engine drive shaft. A portion of the bleed air in the bleed air circuit can be supplied to a system outside the turbine engine. The bleed air circuit including the ATS can be used to extract work from the bleed air so as 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] The exemplary drawings are for illustration purposes only, and the dimensions, positions, orders, and relative sizes reflected in the drawings attached hereto may vary.

[0016] Figure 1 is a schematic perspective view of a turbine engine 14. The turbine engine 14 may include an air turbine starter (ATS) 10. The ATS 10 is coupled to an accessory gearbox (AGB) 12, also referred to as a transmission housing. The AGB 12 includes a housing (not shown) within which are disposed at least a plurality of gears (not shown).

[0017] 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.

[0018] The AGB 12 and ATS 10 are schematically shown mounted to respective portions of the turbine engine 14. At least a portion of the ATS 10 or AGB 12 may be located radially outward of the fan case 28. That is, the ATS 10, 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, 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 or AGB 12 is coupled to a transmission gearbox (not shown).

[0019] 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.

[0020] Figure 2 Yes Figure 1 1 is a schematic block diagram of a bleed air circuit 30 interconnecting a turbine engine 14 and an ATS 10. The ATS 10 is drivingly coupled to the AGB 12 and fluidly coupled to the bleed air circuit 30.

[0021] 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.

[0022] 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.

[0023] The AGB 12 is indirectly operably coupled to the engine drive shaft 44. The AGB 12 includes an AGB drive shaft 78 that defines a mechanical output of the AGB 12. The AGB drive shaft 78 is selectively operably coupled to the engine drive shaft 44. As a non-limiting example, a decoupler 80 may selectively operably couple the AGB drive shaft 78 and the engine drive shaft 44. Alternatively, the AGB drive shaft 78 may be directly coupled to the engine drive shaft 44 or formed integrally with the engine drive shaft 44. The AGB 12 may be operably coupled to any suitable portion of the engine drive shaft 44.

[0024] The turbine engine 14 includes a precooler heat exchanger (PCE) 70 configured to direct bleed air from the turbine engine 14 to an external system 74 disposed outside of the turbine engine 14. The PCE 70 is fluidly coupled to the external system 74 via a bleed air outlet line 64. The external system 74 may include any suitable system that utilizes bleed air from the turbine engine 14 during operation of the external system 74, such as, but not limited to, an environmental control system (ECS). The PCE 70 is also fluidly coupled to a cooling fluid source via a cooling fluid input 72. The cooling fluid source may be from a portion of the turbine engine 14, such as a fan section 16 or a compressor section 18. The PCE 70 may discharge cooling fluid from the cooling fluid source via a cooling fluid output 75. The cooling fluid output 75 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.

[0025] The ATS 10 includes an ATS output shaft 76, 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 76 to define a mechanical output of the ATS gearbox 112 and the ATS 10 as a whole. At least portions of the ATS turbine 114, the ATS gearbox 112, the ATS drive shaft 118, and the ATS output shaft 76 may be received within an ATS housing (not shown).

[0026] 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 three bleed air passages that are directly fluidly coupled to corresponding portions of the turbine engine 14. It will be understood 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 a first LP bleed air passage 46, a second LP bleed air passage 48, and a HP bleed air passage 50. The HP bleed air passage 50 may be coupled to a portion of the turbine engine 14 that has a higher pressure of a working airflow relative to the position at which the first LP bleed air passage 46 and the second LP bleed air passage 48 are disposed. In other words, the HP bleed air passage 50 includes bleed air having a pressure higher than that of the bleed air of the first LP bleed air passage 46 and the bleed air of the second LP bleed air passage 48. The first LP bleed air passage 46 may be coupled to a portion of the turbine engine 14 upstream of the second LP bleed air passage 48. As a non-limiting example, both first LP bleed air passage 46 and second LP bleed air passage 48 may be located upstream of HP bleed air passage 50. Both first LP bleed air passage 46 and second LP bleed air passage 48 may be directly fluidly coupled to LP compressor 34, and HP bleed air passage 50 may be directly fluidly coupled to HP compressor 36.

[0027] The bleed air circuit 30 includes a first bleed air passage 54, a second bleed air passage 56, and a third bleed air passage 58. The first bleed air passage 54 is fluidly coupled to the turbine engine 14 through the first LP bleed air passage 46, the second LP bleed air passage 48, and the HP bleed air passage 50. The second bleed air passage 56 fluidly couples the first bleed air passage 54 to the ATS 10 and defines a fluid input of the ATS 10. The third bleed air passage 58 fluidly couples the ATS 10 to the bleed air inlet 62 that leads directly to the PCE 70.

[0028] The bleed air circuit 30 includes a bypass passage 60 that fluidly couples the first bleed air passage 54 to the third bleed air passage 58 while bypassing the ATS 10 or the second bleed air passage 56. The bypass passage 60 and the third bleed air passage 58 meet at a junction 84. The junction 84 may be disposed upstream of the PCE 70. Alternatively, the bypass passage 60 and the third bleed air passage 58 may be individually and separately coupled to the PCE 70 such that the bypass passage 60 bypasses the ATS 10, and the bypass passage 60 and the third bleed air passage 58 together define a bleed air inlet line 62 leading to the PCE 70. In the case where the bypass passage 60 and the third bleed air passage 58 are independently coupled to the PCE 70, the PCE 70 defines the junction 84. When the PCE 70 outputs to an external system 74 via the bleed air outlet line 64 , the third bleed air passage 58 can be said to fluidly couple the ATS 10 to the external system 74 and the bypass passage 60 can be said to fluidly couple the first bleed air passage 54 to the external system 74 .

[0029] The bleed air circuit 30 may include an auxiliary bleed air passage 66 that is fluidly coupled to an auxiliary system 93 of the turbine engine 14. The auxiliary system 93 is defined as any suitable system of the turbine engine 14 that may utilize bleed air from at least one of the first LP bleed air passage 46, the second LP bleed air passage 48, or the HP bleed air passage 50. As non-limiting examples, the auxiliary system 93 may be an oil cooling system, a wing anti-ice system, a blade anti-ice system, a nacelle anti-ice system, or a combination thereof.

[0030] At least a portion of the bleed air circuit 30, the ATS 10, and the AGB 12 are disposed outside the engine housing 17. As a non-limiting example, the bleed air circuit 30 (except the first LP bleed air passage 46, the second LP bleed air passage 48, and the HP bleed air passage 50), the ATS 10, and the AGB 12 are all disposed outside the engine housing 17.

[0031] The induction air circuit 30 is selectively fluidly coupled to the first LP induction air passage 46 and the second LP induction air passage 48 through a first valve 86. The first valve 86 may include any suitable valve. As a non-limiting example, the first valve 86 may be an on-off valve or a shutoff valve that selectively opens and closes to supply or stop the induction air from the first LP induction air passage 46 and the second LP induction air passage 48, respectively. The first LP induction air passage 46 and the second LP induction air passage 48 mix at a point 52 upstream of the first valve 86 or mix within the first valve 86, so that the first valve 86 may be a mixing valve. It will be understood that by placing corresponding valves along the first LP induction air passage 46 and the second LP induction air passage 48 upstream of the mixing point of the first LP induction air passage 46 and the second LP induction air passage 48, the first LP induction air passage 46 and the second LP induction air passage 48 may supply induction air to the induction air circuit 30 independently of each other.

[0032] The bleed air circuit 30 is correspondingly selectively fluidly coupled to the HP bleed air passage 50 via a second valve 88. The second valve 88 may include any suitable valve. As a non-limiting example, the second valve 88 may be a switch valve or a shutoff valve that selectively opens and closes to supply bleed air from the HP bleed air passage 50 to the bleed air circuit 30 or to stop bleed air from the HP bleed air passage 50 from flowing into the bleed air circuit 30, respectively.

[0033] The induction air circuit 30 includes a third valve 96 arranged along the first induction air passage 54. The third valve 96 may include any suitable valve. As a non-limiting example, the third valve 96 may include a check valve arranged along the junction between the first induction air passage 54 and the second induction air passage 56, which prevents the return flow from the second induction air passage 56 or the bypass passage 60 to the first induction air passage 54. As a non-limiting example, the third valve 96 may include a diverter valve, which transfers all fluids below a specific volume flow rate to the second induction air passage 56, and transfers all fluids above a specific volume flow rate to the bypass passage 60. The diverter valve can be used for the situation where the ATS10 has a specific maximum volume flow rate that it can accept. In this case, the diverter valve can be designed to ensure that the volume flow rate of the fluid in the second induction air passage 56 and supplied to the ATS10 does not exceed the maximum volume flow rate of the ATS10. As a non-limiting example, the ATS10 can have a maximum volume flow rate of about 5 cubic meters per second. In such an example, during operation, if about 6 cubic meters per second of bleed air is supplied through the first bleed air passage 54, the third valve 96 diverts about 5 cubic meters per second of bleed air to the ATS 10 through the second bleed air passage 56, and the third valve 96 supplies the remaining about 1 cubic meter per second of bleed air through the bypass passage 60. The third valve 96 may be disposed at a junction between the first bleed air passage 54, the second bleed air passage 56, and the bypass passage 60.

[0034] The induction air circuit 30 includes a fourth valve 90 disposed along the second induction air passage 56. The fourth valve 90 fluidically couples the second induction air passage 56 to the ATS 10. The fourth valve 90 may include any suitable valve. As a non-limiting example, the fourth valve 90 may include one or more of a check valve or a needle valve for controlling the volume flow rate of the fluid supplied to the ATS 10 in the second induction air passage 56.

[0035] The bleed air circuit 30 may include a fifth valve 92 disposed along the third bleed air passage 58. The fifth valve 92 fluidly couples the third bleed air passage 58 to the bleed air inlet line 62. The fifth valve 92 may include any suitable valve. As a non-limiting example, the fifth valve 92 may include a check valve to prevent backflow into the ATS 10.

[0036] The bleed air circuit 30 may include a sixth valve 98 disposed along the bleed air inlet line 62. The sixth valve 98 fluidly couples the bleed air inlet line 62 to the PCE 70 or otherwise to the external system 74. The sixth valve 98 may include any suitable valve. As a non-limiting example, the sixth valve 98 may include an on-off valve or a shutoff valve.

[0037] The bleed air circuit 30 may include a seventh valve 99 disposed along the auxiliary bleed air passage 66. The seventh valve 99 fluidically couples the first bleed air passage 54 to the auxiliary bleed air passage 66. The seventh valve 99 may include any suitable valve. As a non-limiting example, the seventh valve 99 may include a needle valve for controlling the volume flow rate of the fluid supplied to the auxiliary system 93 in the auxiliary bleed air passage 66.

[0038] It will be understood that the valves of the bleed air circuit 30 can be changed, moved or removed based on the needs of the bleed air circuit 30, and one or more of the valves can include a combination of valves. The turbine engine 14 may include any other suitable valves, such as but not limited to the eighth valve 101 disposed along the cooling fluid input 72. The eighth valve 101 fluidly couples the cooling fluid within the cooling fluid input 72 to the PCE 70. As a non-limiting example, the bleed air circuit 30 may include an orifice plate 100 along the bypass passage 60. The orifice plate 100 may be used to generate a pressure drop along the bypass passage 60 to ensure that the fluid within the bypass passage 60 is at a desired pressure before being supplied to the PCE 70, the external system 74, the confluence 84, or a combination thereof. Although shown as an orifice plate 100, it will be understood that the bypass passage 60 or any other passage of the bleed air circuit 30 may include any suitable member configured to generate a pressure drop along the corresponding passage, such as but not limited to an orifice plate 100, a valve, an ejector, a hole, or a combination thereof.

[0039] The ATS 10 can be selectively fluidly coupled to an external starting system 102 that is configured to supply an air flow to the ATS 10 independently of the bleed air circuit 30. The external starting system 102 can include, for example, a ground cart 104. The external starting system 102 can be selectively fluidly coupled to the ATS 10 via a starting inlet line 68. The starting inlet line 68 can include a starter air valve 97 that can include any suitable valve, such as, but not limited to, an on-off valve. Although described with respect to a ground cart 104, it will be understood that the external starting system 102 can be said to include an air source.

[0040] 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 70 may be eliminated from the turbine engine 14 or otherwise moved to a different location along the bleed air circuit 30. 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.

[0041] 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 86, the second valve 88, the third valve 96, the fourth valve 90, the fifth valve 92, the sixth valve 98, the seventh valve 99, the eighth valve 101, the separator 80, the starter air valve 97, 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, special 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.

[0042] 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.

[0043] 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 high-pressure turbine 40 extracts some work from these gases, and the high-pressure 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.

[0044] 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 or heating. 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.

[0045] During operation, bleed air from a cold section (e.g., the compressor section 18 or the fan section 16) may be selectively drawn into the bleed air circuit 30 through, for example, the first LP bleed air passage 46, the second LP bleed air passage 48, and the HP bleed air passage 50. Since the bleed air circuit 30 may include at least three bleed air passages (e.g., the first LP bleed air passage 46, the second LP bleed air passage 48, and the HP bleed air passage 50), 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 from only a first portion of the LP compressor 34 (e.g., from the first LP bleed air passage 46), only a second portion of the LP compressor 34 (e.g., from the second LP bleed air passage 48), only 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 first LP bleed air passage 46, the second LP bleed air passage 48, the HP bleed air passage 50, or any other bleed air passage directly fluidly coupled to the turbine engine 14 will hereinafter be referred to as circuit bleed air.

[0046] The circuit bleed air from at least one of the first LP bleed air passage 46, the second LP bleed air passage 48, the HP bleed air passage 50, or any other bleed air passage directly fluidly coupled to the turbine engine 14 is then supplied to the first bleed air passage 54. Depending on the operation of the third valve 96, the fourth valve 90, and the seventh valve 99, the circuit bleed air in the first bleed air passage 54 may then be supplied to at least one of the second bleed air passage 56, the bypass passage 60, or the auxiliary bleed air passage 66. As a non-limiting example, if it is determined that the operation of the auxiliary system 93 is desired for the operation of the turbine engine 14 or for other reasons (e.g., wing anti-icing of an aircraft to which the turbine engine is coupled), the seventh valve 99 may be selectively opened by the controller 106 so that at least a portion of the circuit bleed air is supplied to the auxiliary system 93.

[0047] Circuit bleed air may be selectively supplied to the ATS 10 via the second bleed air passage 56. The circuit bleed air supplied to the ATS 10 drives the ATS turbine 114, which in turn drives the ATS output shaft 76. The ATS output shaft 76 may be coupled to or selectively coupled to (e.g., via a clutch, not shown) the AGB 12, such that the ATS output shaft 76 may drive the AGB 12. The drive of the AGB 12 drives the AGB drive shaft 78, which may ultimately drive the engine drive shaft 44. Thus, it will be appreciated that supplying circuit bleed air to the ATS 10 may be used to drive the engine drive shaft 44.

[0048] Driving the engine drive shaft 44 by supplying the circuit bleed air to the ATS 10 can 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 can be driven by the turbine section 22. The ATS 10 can be used to recover energy from the bleed air to enhance the drive of the engine drive shaft 44, so that during operation of the turbine engine 14, the engine drive shaft 44 is partially driven by the turbine section 22 and the ATS 10. It is contemplated that the circuit bleed air can be supplied or selectively supplied to the ATS 10 to enhance the drive 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 can be selectively supplied to the ATS 10 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 ATS 10 can also be used as a brake for the engine drive shaft 44. As a non-limiting example, the ATS 10 may rotate the ATS output shaft 76 or otherwise rotate the AGB drive shaft 78 in an opposite manner to the rotation of the engine drive shaft 44. Thus, the ATS 10 may be used to counteract or otherwise slow the rotation of the engine drive shaft 44.

[0049] The drive of the engine drive shaft 44 by the ATS10 can also be used during one or both of the startup or restart of the turbine engine 14. During startup, air can be supplied to the ATS10 through the bleed air circuit 30 or the external starting system 102 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 restart (for example, when the turbine engine 14 was previously started 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.

[0050] The circuit bleed air supplied to the ATS 10 may then expand as it flows through the ATS turbine 114. This expansion of the circuit bleed air results in a decrease in the pressure and temperature of the circuit bleed air. The third bleed air passage 58 defines a fluid outlet of the ATS 10. Thus, the pressure and temperature of the circuit bleed air supplied to the ATS 10 (via the second bleed air passage 56) is higher than the pressure and temperature of the circuit bleed air supplied from the ATS 10 (via the third bleed air passage 58).

[0051] Subsequently, the loop bleed air in the third bleed air passage 58 may be selectively supplied to the PCE 70 to at least partially define a bleed air inlet line 62 to the PCE 70. At least a portion of the loop bleed air may be supplied to the PCE 70 through the bypass passage 60 to bypass the ATS 10. The amount of loop bleed air supplied through the bypass passage 60 may depend on at least one of the volumetric flow rate of the loop bleed air in the first bleed air passage 54 or the desired pressure of the loop bleed air supplied to the PCE 70 or the external system 74. As a non-limiting example, if the loop bleed air in the third bleed air passage 58 is lower than the desired pressure of the loop bleed air supplied to the external system 74, the bypass passage 60 may supply the loop bleed air (with a higher pressure and temperature than the loop bleed air in the third bleed air passage 58) from the first bleed air passage 54 and mix with the loop bleed air from the third bleed air passage 58 at the confluence 84. This in turn increases the temperature and pressure of the loop bleed air supplied to the PCE 70 or the external system 74 relative to the loop bleed air in the third bleed air passage 58.

[0052] When the loop bleed air is cooled by flowing through the ATS 10, the cooling of the loop bleed air by the PCE 70 can be reduced or eliminated. In other words, the PCE 70 does not need to cool the loop bleed air as much as in the case where the loop bleed air is not first cooled by flowing through the ATS 10. Precooling the loop bleed air before supplying it to the PCE 70 in turn reduces the required size of the PCE 70 and the required amount of cooling fluid supplied to the PCE 70 through the cooling fluid input 72. The amount of cooling of the loop bleed air supplied by the ATS 10 can be large enough so that the loop bleed air in the third bleed air passage 58 is at a sufficiently low temperature that it does not need to be further cooled by the PCE 70 before being supplied to the external system 74. This in turn means that the PCE 70 can be eliminated or otherwise completely bypassed. The amount of cooling fluid supplied to the PCE 70 can be reduced, which means that less air needs to be bleed from the turbine engine 14 or otherwise obtained from other locations of the turbine engine 14 (e.g., through the RAM air structure) 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 74 where it is used to operate the external system 74.

[0053] By using the controller 106, the operation of the ATS 10 can be automatically completed. As a non-limiting example, the controller 106 can operate the ATS 10 by supplying circuit bleed air to the ATS 10 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 the function of anticipating the use of the ATS 10 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 ATS 10 is expected to be used during normal operation of the turbine engine 14. Therefore, the ATS 10 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 ATS 10. 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 required amount of gas fuel needed to produce the combustion gases required to drive the engine drive shaft 44 .

[0054] Benefits associated with the present disclosure include a turbine engine having a 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 an ATS 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.

[0055] 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 an ATS. 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.

[0056] 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 ATS), 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.

[0057] 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.

[0058] 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.

[0059] Further aspects are provided by the subject matter of the following clauses:

[0060] 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 connected to the fan section, the compressor section, and the turbine section; an accessory gearbox (AGB) operably connected to the engine drive shaft; an air turbine starter (ATS) having an ATS turbine, an ATS gearbox, an ATS drive shaft operably connected to the ATS turbine and the ATS gearbox, and an ATS output shaft operably connected to the ATS gearbox and the AGB; and a bleed air circuit including a first bleed air passage fluidly connected to the compressor section, a second bleed air passage fluidly connecting the first bleed air passage to the ATS, a third bleed air passage fluidly connected to the output of the ATS, and a bypass passage fluidly connected to the third bleed air passage while bypassing the ATS.

[0061] A component for a turbine engine, the component including 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; and a bleed air circuit including a first bleed air passage, a second bleed air passage fluidly coupling the first bleed air passage to the ATS, a third bleed air passage fluidly coupled to the output of the ATS, and a bypass passage fluidly coupled to the third bleed air passage while bypassing the ATS.

[0062] 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.

[0063] 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.

[0064] A turbine engine as claimed 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 an input of the PCE and to a system external to the turbine engine to define an output of the PCE.

[0065] 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.

[0066] A turbine engine as claimed in any preceding clause, wherein the system external to the turbine engine comprises an environmental control system.

[0067] 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 third bleed air passage are lower than the temperature and pressure of the working fluid in the second bleed air passage.

[0068] A turbine engine as claimed in any preceding clause, wherein driving the ATS by means of working fluid supplied to the ATS via the second bleed air passage drives the AGB via the ATS drive shaft.

[0069] Turbine engine according to any preceding clause, wherein the AGB is driven by the ATS drive shaft during operation of the turbine engine.

[0070] A turbine engine according to any preceding clause, wherein the ATS is configured to start the turbine engine by driving the ATS output shaft.

[0071] 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.

[0072] A turbine engine according to any preceding clause, wherein, during restart of the turbine engine, the working fluid in the second bleed air passage is supplied to the ATS.

[0073] 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.

[0074] 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.

[0075] A turbine engine as in any preceding clause, wherein the LP bleed air passage comprises a first LP bleed air passage and a second LP bleed air passage, wherein the first LP bleed air passage is fluidly coupled to a portion of the turbine engine upstream of the second LP bleed air passage.

[0076] A turbine engine as in any preceding clause, wherein the compressor section comprises a high pressure (HP) compressor and a low pressure (LP) compressor, wherein the LP bleed air passage is fluidly coupled to the LP compressor and the HP bleed air passage is fluidly coupled to the HP compressor.

[0077] The turbine engine according to any of the preceding clauses further includes a diverter valve defining a junction between the second bleed air passage and the bypass passage, the diverter valve being configured to divert the working fluid in the first bleed air passage between an ATS fluid supplied to the ATS through the second bleed air passage and a bypass fluid supplied to the bypass passage, so that all the working fluid is directed to the ATS until the ATS fluid meets a threshold volume flow rate, and then any excess working fluid exceeding the threshold volume flow rate is directed to the bypass passage.

[0078] A turbine engine as in any preceding clause, wherein the bleed air circuit further comprises an auxiliary system bleed air passage fluidly coupling at least one of the LP bleed air passage or the HP bleed air passage to an auxiliary system.

[0079] The turbine engine according to any of the preceding clauses further includes a controller configured to automatically and selectively supply the working fluid in the first bleed air passage to at least one of the ATS or the bypass passage based on at least one of the rotational speed or torque of the engine drive shaft or the requirements of a system external to the turbine engine.

[0080] A turbine engine according to any preceding clause, further comprising an engine casing housing an engine core, wherein the ATS is arranged outside the engine casing.

[0081] A turbine engine according to any preceding clause, further comprising a first valve arranged along the low pressure bleed air passage.

[0082] A turbine engine as claimed in any preceding clause, wherein the first valve selectively fluidly couples bleed air from the turbine engine via the LP bleed air passage to the first bleed air passage.

[0083] A turbine engine as claimed in any preceding clause, wherein the first valve is arranged downstream of a junction of the first LP bleed air passage and the second LP bleed air passage.

[0084] A turbine engine as claimed in any preceding clause, wherein the first valve is a mixing valve for the first LP bleed air passage and the second LP bleed air passage.

[0085] A turbine engine according to any preceding clause, further comprising a second valve arranged along the HP bleed air passage.

[0086] A turbine engine as claimed in any preceding clause, wherein the second valve selectively fluidly couples bleed air from the turbine engine via the HP bleed air passage to the first bleed air passage.

[0087] A turbine engine according to any preceding clause, further comprising a third valve arranged along the first bleed air passage.

[0088] A turbine engine as claimed in any preceding clause, wherein the third valve selectively fluidly couples the circuit bleed air from the first bleed air passage to at least one of the second bleed air passage or the bypass passage.

[0089] A turbine engine as claimed in any preceding clause, wherein the third valve is provided at a junction between the second bleed air passage and the bypass 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 circuit bleed air from the first bleed air passage to the ATS.

[0092] A turbine engine according to any preceding clause, further comprising a fifth valve arranged along the third bleed air passage.

[0093] A turbine engine as in any preceding clause, wherein a fifth valve selectively fluidly couples circuit bleed air from the ATS to the PCE or an external system.

[0094] The turbine engine according to any preceding clause, further comprising a sixth valve selectively fluidly coupling at least one of the bypass passage or the third bleed air passage to the PCE or an external system.

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

[0096] A turbine engine as claimed in any preceding clause, wherein the seventh valve selectively fluidly couples the circuit bleed air from the first bleed air passage to the auxiliary system.

[0097] A turbine engine according to any preceding clause, further comprising an orifice plate arranged along the bypass passage.

[0098] A method of operating a turbine engine according to any preceding clause, the method comprising supplying bleed air from the turbine engine to an ATS.

[0099] A method according to any preceding clause, further comprising driving the ATS output shaft via bleed air supplied to the ATS.

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

[0101] A method according to any preceding clause, further comprising driving the engine drive shaft at least partially via the ATS output shaft during operation of the turbine engine.

[0102] 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 ATS.

[0103] The method of any preceding clause, further comprising supplying bleed air from the turbine engine and supplying the bleed air to the ATS 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, and a turbine section arranged in series flow; 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; 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 the ATS; a third bleed air passage fluidly coupled to an output of the ATS; and A bypass passage is fluidly coupled to the third bleed air passage while bypassing the ATS. 2 . The turbine engine according to claim 1 , further comprising a precooler heat exchanger (PCE) fluidly coupled to the fan section and to a system external to the turbine engine.

3. The turbine engine according to claim 2, wherein: The third air induction passage and the bypass passage meet at a confluence portion upstream of the PCE.

4. The turbine engine according to claim 2, wherein: The PCE is selectively fluidly coupled to at least one of the third bleed air passage or the bypass passage to define an input of the PCE, and is fluidly coupled to a system external to the turbine engine to define an output of the PCE.

5. The turbine engine according to claim 4, 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.

6. The turbine engine according to claim 2, wherein: Systems external to the turbine engine include an environmental control system.

7. The turbine engine according to claim 1, wherein: The second air induction channel and the third air induction channel each include a corresponding working fluid having a corresponding temperature and a corresponding pressure; and The temperature and pressure of the working fluid in the third air induction passage are lower than the temperature and pressure of the working fluid in the second air induction passage.

8. The turbine engine according to claim 1, wherein: The ATS is driven by the working fluid supplied to the ATS through the second bleed air passage, and the AGB is driven through the ATS drive shaft.

9. The turbine engine according to claim 8, wherein: The AGB is driven by the ATS drive shaft during operation of the turbine engine.

10. The turbine engine according to claim 1, wherein: The ATS is configured to start the turbine engine by driving the ATS output shaft.

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