Turbine engine including an air turbine starter and a bleed air circuit

A turbine engine including an engine core, an engine drive shaft, an accessory gear box (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 serial flow arrangement. The 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.

TECHNICAL FIELD

The disclosure generally relates to a turbine engine including an air turbine starter, and more specifically to a bleed air circuit from the turbine engine.

BACKGROUND

A turbine engine, for example a gas turbine engine, utilizes an air turbine starter (ATS) during startup of the turbine engine. The ATS is often mounted near the turbine engine and the ATS can be coupled to a high-pressure fluid source, such as compressed air, which impinges upon a turbine rotor in the ATS causing it to rotate at a relatively high rate of speed. The ATS includes an output drive shaft that is driven by the turbine rotor, typically through a reducing gear box, where the output drive shaft provides rotational energy to a rotatable element of the turbine engine (e.g., the crankshaft or the rotatable shaft) to begin rotating. The rotation by the ATS continues until the turbine engine attains a self-sustaining operating rotational speed.

DETAILED DESCRIPTION

Aspects of the present disclosure are directed to a turbine engine including an ATS, a bleed air turbo (BAT) and a bleed air circuit drawing bleed air from the turbine engine. The turbine engine includes an engine drive shaft. The BAT and the ATS are each independently coupled to an accessory gearbox (AGB). The AGB is selectively coupled to the engines drive shaft. Driving of the ATS and the BAT can each drive the engine drive shaft through driving of the AGB.

The bleed air circuit is used to feed bleed air from the turbine engine to at least the BAT. Driving of the BAT, through the bleed air, drives the AGB, which drives the engine drive shaft. A portion of the bleed air within the bleed air circuit can be fed to a system external to the turbine engine. The bleed air circuit including the BAT can be used to extract a work from the bleed air in order to augment the driving of the engine drive shaft. For purposes of illustration, the present disclosure will be described with respect to a turbine engine. It will be understood, however, that aspects of the disclosure described herein are not so limited and can have general applicability for other engines or other turbine engines. For example, the disclosure can have applicability for an engine starter assembly used with any suitable engine or within any suitable vehicle, and can be used to provide benefits in industrial, commercial, and residential applications.

As used herein, the term “upstream” refers to a direction that is opposite the fluid flow direction, and the term “downstream” refers to a direction that is in the same direction as the fluid flow. The term “fore” or “forward” means in front of something and “aft” or “rearward” means behind something. For example, when used in terms of fluid flow, fore/forward can mean upstream and aft/rearward can mean downstream.

Additionally, as used herein, the terms “radial” or “radially” refer to a direction extending towards or away from a common center. For example, in the overall context of a turbine engine, radial refers to a direction along a ray extending between a center longitudinal axis of the turbine engine and an outer engine circumference. Furthermore, as used herein, the term “set” or a “set” of elements can be any number of elements, including only one.

As used herein, a “controller” can include at least one processor and memory. Non-limiting examples of the memory can include Random Access Memory (RAM), Read-Only Memory (ROM), flash memory, or one or more different types of portable electronic memory, such as discs, DVDs, CD-ROMs, etc., or any suitable combination of these types of memory. The processor can be configured to run any suitable programs or executable instructions designed to carry out various methods, functionality, processing tasks, calculations, or the like, to enable or achieve the technical operations or operations described herein. The program can include a computer program product that can include machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media, which can be accessed by a general purpose or special purpose computer or other machine with a processor. Generally, such a computer program can include routines, programs, objects, components, data structures, algorithms, etc., that have the technical effect of performing particular tasks or implement particular abstract data types.

The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto can vary.

FIG.1is a schematic perspective view of a turbine engine14. The turbine engine14can include an air turbine starter (ATS)10and a bleed air turbo (BAT)46. The ATS10is coupled to an accessory gear box (AGB)12, also known as a transmission housing. The BAT46is coupled to the AGB12. The AGB12includes a housing (not illustrated) with at least a plurality of gears (not illustrated) provided within the housing.

The turbine engine14can include in a serial flow arrangement a fan section16, a compressor section18, a combustion section20, a turbine section22, and an exhaust section26. The fan section16can be at least partially encased by a fan casing28or otherwise by a nacelle or casing of the turbine engine14. The turbine engine14can include other components not illustrated.

The AGB12, the ATS10, and the BAT46are schematically illustrated as being mounted to a respective portion of the turbine engine14. At least a portion of the ATS10, the BAT46or the AGB12can be located radially outside of a fan casing28. That is, the ATS10, the BAT46, the AGB12, or a combination thereof can be located radially outside of the fan section16. Alternatively, it is contemplated that in a differing and non-limiting example, at least a portion of the ATS10, the BAT46, the AGB12, or a combination thereof can be located within any suitable portion of the turbine engine14such as near the compressor section18, where the ATS10, the BAT46or the AGB12can be coupled to a transfer gear box (not shown).

The AGB12can be coupled to the turbine engine14at a portion of the turbine section22by way of a mechanical power take-off27. The mechanical power take-off27contains multiple gears and means for mechanical coupling of the AGB12to the turbine engine14.

FIG.2is a schematic block diagram of a bleed air circuit30interconnecting the turbine engine14and the ATS10ofFIG.1.

The fan section16, the compressor section18, the combustion section20and the turbine section22collectively define an engine core15. At least a portion of the engine core15can be provided within an engine casing17that is coupled to the fan casing28(FIG.1) or nacelle. Any suitable portion of the turbine engine14can be provided within the engine casing17.

The compressor section18can include a low pressure (LP) compressor34and a high pressure (HP) compressor36in serial flow arrangement. The turbine section22can include a high pressure (HP) turbine40and a low pressure (LP) turbine42in serial flow arrangement. The combustion section20can include a combustor38provided between and fluidly coupling the HP compressor36to the HP turbine40. An engine drive shaft44drivingly couples the turbine section22to the compressor section18and the fan section16. While not illustrated, the engine drive shaft44can include a high pressure (HP) shaft drivingly coupling the HP turbine40to the HP compressor36to collectively define an HP spool, and a low pressure (LP) shaft drivingly coupling the LP turbine42to the LP compressor34and the fan section16to collectively define an LP spool.

The BAT46includes a BAT output shaft48and a BAT turbine116drivingly coupled to the BAT output shaft48. The BAT output shaft48is drivingly coupled to the AGB12.

The ATS10includes an ATS output shaft50, an ATS gearbox112, an ATS drive shaft118, and an ATS turbine114. The ATS turbine114is drivingly coupled to the ATS gearbox112through the ATS drive shaft118to define a mechanical input to the ATS gearbox112. The ATS gearbox112is coupled to the ATS output shaft50to define a mechanical output of the ATS gearbox112and the ATS10as a whole. The ATS turbine114, the ATS gearbox112, the ATS drive shaft118, and at least a portion of the ATS output shaft50can be received within an ATS housing (not illustrated). Both of the BAT output shaft48and the ATS output shaft50define a mechanical input to the AGB12.

The BAT46can be similar to the ATS10in that both the ATS10and the BAT include a respective turbine (e.g., the ATS turbine114and the BAT turbine116, respectively) and a receptive output drive shaft (e.g., the ATS output shaft50and the BAT output shaft48, respectively. However, the BAT46can be formed without a respective gearbox and can be coupled to the AGB12through the BAT output shaft48, while the ATS10includes the ATS gearbox112and can include the ATS output shaft50that can be selectively couplable to the AGB12through a clutch or a decoupler. Alternatively, the BAT46can include a gearbox. As the BAT output shaft48is coupled to the AGB12, any rotation of the BAT turbine116(e.g., through supplying bleed air to the BAT46) will cause a transfer of energy from the BAT46to the AGB12through the BAT output shaft48. As the ATS10includes a decoupler or a clutch, rotation of the ATS turbine114does not mean that energy will be transferred to the AGB12from the ATS10through the ATS output shaft50unless the clutch or decoupler of the ATS10is intentionally engaged.

The AGB12is operably coupled to the engine drive shaft44. As illustrated, the AGB12is indirectly operably coupled to the engine drive shaft44. The AGB12includes an AGB drive shaft52defining a mechanical output of the AGB12. The AGB drive shaft52is selectively operably coupled to the engine drive shaft44. As a non-limiting example, a decoupler54can selectively operably couple the AGB drive shaft52and the engine drive shaft44. Alternatively, the AGB drive shaft52can be directly coupled to or integrally formed with the engine drive shaft44. The AGB12is operably coupled to any suitable portion of the engine drive shaft44.

The turbine engine14includes a Pre-Cooler heat Exchanger (PCE)78configured to direct a bleed air from the turbine engine14to an external system86that is provided external the turbine engine14. The PCE 78 is fluidly coupled to the external system86through a bleed air outlet line70. The external system86can include any suitable system that utilizes a bleed air from the turbine engine14during operation of the external system86such as, but not limited to, an Environmental Control System (ECS). The PCE 78 is further fluidly coupled to a source of cooling fluid through a cooling fluid input80. The source of cooling fluid can be a portion of the turbine engine14such as the fan section16or the compressor section18. The PCE 78 can exhaust a cooling fluid received from the source of cooling fluid through a cooling fluid output82. The cooling fluid output82can be fluidly coupled to atmosphere or to a portion of the turbine engine14such as the turbine section22, the exhaust section26(FIG.1) of the turbine engine14, or a combination thereof.

The bleed air circuit30is fluidly coupled to the turbine engine14and is configured to draw bleed air from at least one portion of the turbine engine14. The bleed air circuit30can include two bleed air passages directly fluidly coupled to a respective portion of the turbine engine. It will be appreciated that the passages of the bleed air circuit30can be formed as discrete elements (e.g., conduits) or otherwise be integrally formed within an existing structure of, for example, the turbine engine14. As a non-limiting example, the bleed air circuit30can include an LP bleed air passage56and an HP bleed air passage58. The HP bleed air passage58can be coupled to a portion of the turbine engine14with a higher-pressure working airflow with respect to where the LP bleed air passage56is provided. In other words, the HP bleed air passage58includes bleed air having a higher pressure than bleed air of the LP bleed air passage56. As a non-limiting example, the LP bleed air passage56can be directly fluidly coupled to the LP compressor34and the HP bleed air passage58can be directly fluidly coupled to the HP compressor36.

The bleed air circuit30comprises a first bleed air passage60, a second bleed air passage62and a third bleed air passage64. The first bleed air passage60is fluidly coupled to the turbine engine14through the LP bleed air passage56and the HP bleed air passage58. The second bleed air passage62fluidly couples the first bleed air passage60to the BAT46and defines a fluid input to the BAT46. The third bleed air passage64fluidly couples the BAT46to a bleed air inlet68leading directly to the PCE 78.

The bleed air circuit30includes a bypass passage66fluidly coupling the first bleed air passage60to the third bleed air passage64while bypassing the BAT46or the second bleed air passage62. The bypass passage66and the third bleed air passage64meet at a junction88. The junction88can be provided upstream of the PCE 78. Alternatively, the bypass passage66and the third bleed air passage64can be individually, separately coupled to the PCE 78 such that the bypass passage66bypasses the BAT46, and the bypass passage66and the third bleed air passage64, together, define the bleed air inlet line68leading to the PCE 78. With the bypass passage66and the third bleed air passage64being independently coupled to the PCE 78, the PCE 78 defines the junction88. As the PCE 78 outputs to the external system86, via the bleed air outlet line70, the third bleed air passage64can be said to fluidly couple to the BAT46to the external system86and the bypass passage66can be said to fluidly couple the first bleed air passage60to the external system86.

The bleed air circuit30includes a fourth bleed air passage72defining a fluid input to the ATS10. The fourth bleed air passage72can be fluidly coupled to any suitable portion of the bleed air circuit30. As a non-limiting example, the fourth bleed air passage72can be fluidly coupled to the bleed air outlet line70. The ATS10can exhaust the fluid received from the fourth bleed air passage72through an exhaust line84. The exhaust line84can be fluidly coupled to atmosphere or to a portion of the turbine engine14such as the fan section16, the compressor section18, the turbine section22, an exhaust section26of the turbine engine14, or a combination thereof.

The bleed air circuit30can include an auxiliary bleed air passage74that is fluidly coupled to an auxiliary system76of the turbine engine14. The auxiliary system76is defined as any suitable system of the turbine engine14that can utilize bleed air from at least one of the HP bleed air passage58or the LP bleed air passage56. As a non-limiting example, the auxiliary system76can include an oil cooling system, a wing anti-ice system, a blade anti-ice system, a nacelle anti-ice system, or a combination thereof.

At least a portion of the bleed air circuit30, the ATS10, the AGB12and the BAT46are provided exterior the engine casing17. As a non-limiting example, all of the bleed air circuit30(besides the LP bleed air passage56and the HP bleed air passage58), the ATS10, the AGB12and the BAT46are provided exterior the engine casing17.

The bleed air circuit30is selectively fluidly coupled to the LP bleed air passage56and the HP bleed air passage58through a first valve90and a second valve92, respectively. The first valve90and the second valve92can include any suitable valve. As a non-limiting example, the first valve90can include a check valve such that bleed air is fed through the LP bleed air passage56during operation of the turbine engine14. As a non-limiting example, the first valve90can include an on-off valve such that bleed air is selectively fed through the LP bleed air passage56during operation of the turbine engine14. As a non-limiting example, the second valve92can include an on-off or stop valve that selectively opens and closes to supply or stop, respectively, bleed air from the HP bleed air passage58from flowing into the bleed air circuit30. As a non-limiting example, the second valve92can include a check valve such that bleed air is fed through the HP bleed air passage58during operation of the turbine engine14.

The bleed air circuit30comprises a third valve94provided along the first bleed air passage60. The third valve94can include any suitable valve. As a non-limiting example, the third valve94can include a check valve provided along a junction between the first bleed air passage60and the second bleed air passage62that prevents backflow from the second bleed air passage62or the bypass passage66into the first bleed air passage60. As a non-limiting example, the third valve94can include a split valve that diverts all fluid under a certain volumetric flow rate to the second bleed air passage62and all fluid over the certain volumetric flow rate to the bypass passage66. The split valve can be used in an instance where the BAT46has a certain maximum volumetric flow rate that it can accept. The split valve, in this instance, can be sized to ensure that the volumetric flow rate of the fluid within the second bleed air passage62and being fed to the BAT46does not exceed the maximum volumetric flow rate of the BAT46. The third valve94can be provided at a junction between the first bleed air passage60, the second bleed air passage62and the bypass passage66.

The bleed air circuit30comprises a fourth valve96provided along the second bleed air passage62. The fourth valve96fluidly couples the first bleed air passage60to the BAT46. The fourth valve96can include any suitable valve. As a non-limiting example, the fourth valve96can include a needle valve used to control the volumetric flow rate of the fluid within the second bleed air passage62being fed to the BAT46.

The bleed air circuit30can include a fifth valve98provided along the bleed air inlet line68. The fifth valve98fluidly couples the bleed air inlet line68to the PCE 78 or otherwise to the external system86. The fifth valve98can include any suitable valve. As a non-limiting example, the fifth valve98can include an on-off or stop valve.

The bleed air circuit30can include a sixth valve100provided along the fourth bleed air passage72. The sixth valve100fluidly couples the bleed air outlet line70to the ATS10. The sixth valve100can include any suitable valve. As a non-limiting example, the sixth valve100can include an on-off or stop valve.

The bleed air circuit30can include a seventh valve102provided along the auxiliary bleed air passage74. The seventh valve102fluidly couples the first bleed air passage60to the auxiliary bleed air passage74. The seventh valve102can include any suitable valve. As a non-limiting example, the seventh valve102can include an on-off or stop valve.

It will be appreciated that the valves of the bleed air circuit30can be changed, moved, or removed based on the need of the bleed air circuit30. The turbine engine14can include any other suitable valves such as, but not limited to, an eighth valve104provided along the cooling fluid input80. The eighth valve104can fluidly couple the cooling fluid within the cooling fluid input80to the PCE 78. As a non-limiting example, the bleed air circuit30can include any suitable component along a respective passage of the bleed air circuit30that is configured to create a pressure drop along the respective passage. As a non-limiting example, the bypass passage66can include an orifice plate to ensure that the fluid within the bypass passage66is at a desired pressure prior to being fed to the PCE 78, external system86, the junction88or a combination thereof. The component configured to create a pressure drop along the respective passage can be any suitable component such as, but not limited to, an orifice plate, a valve, an ejector, an orifice, or a combination thereof.

It will be appreciated that components of the bleed air circuit30or the turbine engine14can be moved, replaced, or removed with respect to the illustrated configuration. For example, the PCE 78 can be excluded from the turbine engine14or otherwise moved to a differing location along the bleed air circuit30. As a non-limiting example, the fourth bleed air passage72can be provided upstream of the PCE 78. As a non-limiting example, the bleed air circuit30can include additional or differing placements of the bleed air passages configured to draw bleed air from the turbine engine14including, but not limited to, the fan section16, the compressor section18, the turbine section22the exhaust section26, or a combination thereof.

A controller106(e.g., an electronic controller) can be used to selectively, operably control certain portions of turbine engine14. As a non-limiting example, the controller106can be used to selectively, operably control the first valve90, the second valve92, the third valve94, the fourth valve96, the fifth valve98, the sixth valve100, the seventh valve102, the eighth valve104, the decoupler54, any other valve, or any combination thereof. The controller106can include a processor108and a memory110, and can be communicatively coupled to respective portions of the bleed air circuit30or turbine engine14. The memory110can be defined as an internal storage for instructions and code for controlling or monitoring various aspects of the bleed air circuit30or turbine engine14. For example, the memory110can store code, executable instructions, commands, instructions, authorization keys, specialized data keys, passwords, or the like. The memory110can be RAM, ROM, flash memory, or one or more different types of portable electronic memory, such as discs, DVDs, CD-ROMs, etc., or any suitable combination of these types of memory. The processor108can be defined as a portion of the controller106which can receive an input, perform calculations, and output executable data. The processor108can include a microprocessor. While described in terms of the controller106, it will be appreciated that the controller106can be a control system including multiple separate controllers coupled to respective portions of the turbine engine14. The control system can collectively define a system used to automatically control operation of the turbine engine14and the bleed air circuit30.

During operation of the turbine engine14, a freestream airflow flows against a forward portion of the turbine engine14. A portion of the freestream airflow enters the fan section16to define an inlet airflow. A portion of the inlet airflow enters the engine core15defining a working airflow, which is used for combustion within the engine core15.

More specifically, the working airflow flows into the LP compressor34, which then pressurizes the working airflow thus defining a pressurized airflow that is supplied to the HP compressor36, which further pressurizes the air. The working airflow, or the pressurized airflow, from the HP compressor36is mixed with fuel in the combustor38and ignited, thereby generating combustion gases. Some work is extracted from these gases by the HP turbine40, which drives the HP compressor36through the engine drive shaft44. The combustion gases are discharged into the LP turbine42, which extracts additional work to drive the LP compressor34, and the working airflow, or exhaust gas, is ultimately discharged from the turbine engine14via an exhaust section26. The driving of the LP turbine42drives the engine drive shaft44to rotate the fan section16and the LP compressor34.

It is contemplated that a portion of the working airflow is drawn as bleed air (e.g., from the compressor section18). The bleed air provides an airflow to engine components requiring cooling. The temperature of the working airflow exiting the combustion section20is significantly increased with respect to the working airflow within the compressor section18. As such, cooling provided by the bleed air is necessary for operating of such engine components in heightened temperature environments or a hot portion of the unducted turbine engine14.

During operation, bleed air from the cold portions (e.g., the compressor section18or the fan section16) can be selectively drawn into the bleed air circuit30through, for example, the LP bleed air passage56and the HP bleed air passage58. As the bleed air circuit30can include at least two bleed air passages (e.g., the LP bleed air passage56and the HP bleed air passage58), bleed air from at least one location within the turbine engine14can be supplied to the bleed air circuit30. As a non-limiting example, bleed air from only the LP compressor34, only the HP compressor36, or a combination thereof can be supplied to the bleed air circuit30. The fluid provided to the bleed air circuit30through at least one of the LP bleed air passage56, the HP bleed air passage58, or any other bleed air passage directly fluidly coupled to the turbine engine14will hereinafter be referred to as the circuit bleed air.

The circuit bleed air from at least one of the LP bleed air passage56, the HP bleed air passage58, or any other bleed air passage directly fluidly coupled to the turbine engine14is then fed to the first bleed air passage60, The circuit bleed air in the first bleed air passage60can then be fed to at least one of any of the second bleed air passage62, the bypass passage66or the auxiliary bleed air passage74depending on the operation of the third valve94, fourth valve96and seventh valve102. As a non-limiting example, if it is determined that operation of the auxiliary system76is desired for operation of the turbine engine14or for another reason (e.g., wing anti-icing of an aircraft that the turbine engine is coupled to), the seventh valve102can be selectively opened, via the controller106, such that at least a portion of the circuit bleed air is fed to the auxiliary system76.

The circuit bleed air can be selectively fed to the BAT46through the second bleed air passage62. The circuit bleed air fed to the BAT46drives the BAT turbine, which thereby drives the BAT output shaft48. The BAT output shaft48can be coupled to or selectively coupled to (e.g., through a clutch, not illustrated) the AGB12such that the BAT output shaft48can drive the AGB12. The driving of the AGB12drives the AGB drive shaft52, which can ultimately drive the engine drive shaft44. As such, it will be appreciated that supplying of the circuit bleed air to the BAT46can be used to drive the engine drive shaft44. The circuit bleed air can be fed to the ATS10through the fourth bleed air passage72to drive the ATS turbine114, which drives the ATS output shaft50. The ATS output shaft50is coupled to or selectively coupled to (e.g . . . , through a clutch, not illustrated) the AGB12. The driving of the AGB12drives the AGB drive shaft52, which can drive the engine drive shaft44.

The driving of the engine drive shaft44, through supplying the circuit bleed air to the BAT46can be used to augment at least one of a rotational velocity or torque of the engine drive shaft44. In other words, the engine drive shaft44can be driven, by the turbine section22, during normal operation of the turbine engine14. The BAT46can be used to recoup energy from the bleed air in order to augment the driving of the engine drive shaft44such that the engine drive shaft44is driven, in part, by the turbine section22and the BAT46during operation of the turbine engine14. It is contemplated that the circuit bleed air can be fed to or selectively fed to the BAT46to augment the driving of the engine drive shaft44. As a non-limiting example, if at least one of a sensed torque or rotational velocity of the engine drive shaft44is lower than a needed torque or rotational velocity of the engine drive shaft44, the circuit bleed air can be selectively fed to the BAT46to ultimately increase at least one of the torque or the rotational velocity of the engine drive shaft44, such as up to the needed torque or rotational velocity. It is contemplated that the BAT46can further be used as a brake to the engine drive shaft44. As a non-limiting example, the BAT46can rotate the BAT output shaft48or otherwise cause the AGB drive shaft52to rotate counter the rotation of the engine drive shaft44. As such, the BAT46can be used to counter or otherwise slow down the rotation of the engine drive shaft44.

The driving of the engine drive shaft44through the ATS10can be used during one or both of startup or restart of the turbine engine14. During startup, air can be fed to the ATS10through the bleed air circuit30or from an exterior source (e.g., a ground cart) to drive the engine drive shaft44to start the drawing in of air through the fan section16to begin the process of compressing and combusting the working airflow. During restart (e.g., when the turbine engine14has previously started but has ceased to continue running), the engine drive shaft44can begin winding down such that the engine drive shaft44decreases in rotational velocity but still draws in air to define the working airflow and bleed air. The circuit bleed air can be fed to the ATS10through the bleed air circuit30. The ATS10can then increase the rotational speed of the engine drive shaft44such that the turbine engine14can continue to draw in the working airflow and subsequently attempt to restart the turbine engine14by combusting the compressed airflow.

It is contemplated that the engine drive shaft44can include a first demand of a transfer of energy from the ATS10in order to startup or restart the turbine engine14. It is contemplated that the engine drive shaft can have a second demand of a transfer of energy from the BAT46during normal operation of the turbine engine14. The second demand is smaller than the first demand as the BAT46is used when the engine drive shaft44is already rotating due to the operation of the turbine engine14, while the ATS10is used when the engine drive shaft44is winding down or otherwise not moving. As such, the ATS10requires the use of the ATS gearbox112to ensure that the output of the ATS10through the ATS output shaft50is at a sufficient level to meet the first demand. As the second demand is smaller than the first demand, the BAT46does not require the use of a respective gearbox to ensure that that the output of the BAT46through the BAT output shaft48is at a sufficient level to the meet the second demand. Further, as the ATS10includes the ATS gearbox112, it can be required to decouple the ATS10from the AGB12or otherwise ensure that bleed air is not fed to the ATS10during normal operation of the turbine engine14to ensure that the second demand is not exceeded. As such, it has been found to be advantageous to include a separate turbine (e.g., the BAT46) that can be used during normal operation of the turbine engine14to ensure that the second demand is not exceeded.

The circuit bleed air that is fed to the BAT46can subsequently be expanded as it flows through the BAT turbine of the BAT46. This expansion of the circuit bleed air causes the circuit bleed air to be lowered in pressure and temperature. The third bleed air passage64defines a fluid outlet of the BAT46. As such, the circuit bleed air being fed to the BAT46(through the second bleed air passage62) has a pressure and temperature that is higher than the pressure and temperature of the circuit bleed air being fed from the BAT46(through the third bleed air passage64).

The circuit bleed air within the third bleed air passage64can subsequently be selectively fed to the PCE 78 to at least partially define the bleed air inlet line68to the PCE 78. At least a portion of the circuit bleed air can bypass the BAT46by being fed to the PCE 78 through the bypass passage66. The amount of circuit bleed air fed through the bypass passage66can be dependent on at least one of a volumetric flow rate of the circuit bleed air in the first bleed air passage60or a required pressure of the circuit bleed air being fed to the PCE 78 or external system86. As a non-limiting example, if the circuit bleed air within the third bleed air passage64is lower than a required pressure of the circuit bleed air that is fed to the external system86, the bypass passage66can supply a circuit bleed air from the first bleed air passage (higher pressure and temperature than the circuit bleed air in the third bleed air passage64) and mix, at the junction88, with the circuit bleed air from the third bleed air passage64. This, in turn, raises the temperature and pressure of the circuit bleed air being fed to the PCE 78 or external system86with respect to the circuit bleed air in the third bleed air passage64.

As the circuit bleed air is cooled by flowing through the BAT46, the cooling of the circuit bleed air done 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 in comparison with a scenario where the circuit bleed air is not first cooled by flowing through the BAT46. This pre-cooling of the circuit bleed air prior to it being fed to the PCE 78 in turn reduces the needed size of the PCE 78 and the needed amount of cooling fluid being fed to the PCE 78 through the cooling fluid input80. The amount of that the circuit bleed air that is fed through the BAT46and cooled can be large enough such that the circuit bleed air in the third bleed air passage64is at a sufficiently lower temperature that it does not need to be further cooled by the PCE 78 prior to being fed to the external system86. This, in turn, means that the PCE 78 can be eliminated or otherwise bypassed altogether. The quantity of the cooling fluid fed to the PCE 78 can be reduced, this means that less air needs to be bled from the turbine engine14or otherwise sourced from other locations of the turbine engine14(e.g., through a RAM air configuration) to form the cooling fluid. This, in turn, means that more air is available to be compressed and combusted, thus increasing the rotational speed and torque of the engine drive shaft44. The circuit bleed air in the bleed air circuit30can ultimately be fed to the external system86where it is used to operate the external system86.

The operation of the BAT46and the ATS10can be done automatically through use of the controller106. As a non-limiting example, the controller106can operate the BAT46by supplying circuit bleed air to the BAT46in order to augment the power of the engine drive shaft44based on a measured torque or speed of the engine drive shaft44alongside a required output of the turbine engine14. As a non-limiting example, the controller106can include in the memory110or otherwise within a memory accessible to the controller106a function that anticipates the use of the BAT46to augment the power of the engine drive shaft44during normal operation of the turbine engine14. In other words, the turbine engine14can be operated in such a fashion that it is anticipated that the BAT46will be used during normal operation of the turbine engine14. As such, the BAT46can be used to augment the power of the engine drive shaft44even if the turbine engine14is able to produce the needed output without the use of BAT46. This, in tun, allows for more efficient operation of the turbine engine14as the turbine engine14can extract additional work from the bleed air to augment the power of the engine drive shaft44, thus lowering a required amount of gaseous fuel needed to produce the needed combustion gases to drive the engine drive shaft44.

Benefits associated with the present disclosure include a turbine engine with increased efficiency when compared to a conventional turbine engine. For example, traditional turbine engines can include a bleed air circuit that feeds bleed air to an external system. Work, however, is not extracted from this bleed air in order to drive the engine drive shaft. The turbine engine as descried herein, however, includes the bleed air circuit with the BAT that extracts work from the bleed air prior to it being fed to the external system. This extracted work, in turn, is used to augment the driving of the engine drive shaft. In other words, work is extracted from the bleed air which, in turn, increases the turbine engine efficiency when compared to the conventional turbine engine.

Additional benefits of the present disclosure include a decreased footprint or elimination of the PCE. For example, conventional turbine engines that include a bleed air circuit used to feed bleed air to the external system require the PCE to cool the bleed air to the required temperature of the external system. The bleed air circuit as described herein, however, can pre-cool the bleed air through the BAT. The pre-cooling of the bleed air can, in turn, reduce the size of or otherwise fully eliminate the need of the PCE when compared to the conventional bleed air circuit.

Additional benefits of the present disclosure include a bleed air circuit that is able to both augment the driving of the engine drive shaft, and at least one of start or restart the turbine engine. The bleed air circuit, as described herein, includes both the BAT and the ATS such that bleed air from the turbine engine can be used to augment the driving of the engine drive shaft or restart the turbine engine while still supplying bleed air to the auxiliary systems or external systems.

Additional benefits of the present disclosure include an increased amount of bleed air that is drawn from the turbine engine when compared to the conventional turbine engine. For example, in the conventional turbine engine the extracted bleed air is not used to augment the power of the engine drive shaft. If too much bleed air is drawn from the turbine engine, not enough combustion gases will be generated or the combustion gases will not be at a needed pressure. This, in turn, can cause the conventional turbine engine to stall. The turbine engine as described herein, however, uses the bleed air to augment the power of the engine drive shaft (e.g., through the BAT), which in turn means that more bleed air can be drawn from the turbine engine without fear of stalling the turbine engine. As more bleed air can be drawn from the turbine engine with respect to the conventional turbine engine, more bleed air can be fed to auxiliary systems or external systems, thus increasing the efficiency of the systems that the bleed air is fed to.

To the extent not already described, the different features and structures of the various aspects can be used in combination, or in substitution with each other as desired. That one feature is not illustrated in all of the examples is not meant to be construed that it cannot be so illustrated, but is done for brevity of description. Thus, the various features of the different aspects can be mixed and matched as desired to form new aspects, whether or not the new aspects are expressly described. All combinations or permutations of features described herein are covered by this disclosure.

A turbine engine, comprising an engine core comprising a fan section, a compressor section, a combustion section, and a turbine section in serial flow arrangement, an engine drive shaft operably coupling the fan section, the compressor section and the turbine section, an accessory gear box (AGB) operably 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 turbo (BAT) including a BAT turbine, and a BAT output shaft, the BAT output shaft being operably coupled to the AGB, and 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 fluidly coupled to the third bleed air passage while bypassing the BAT.

An assembly for a turbine engine, the assembly comprising an accessory gear box (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 turbo (BAT) including a BAT turbine, and a BAT output shaft, the BAT output shaft being 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.

The turbine engine of any preceding clause, wherein the driving of the BAT, through a working fluid supplied to the BAT through the second bleed air passage, drives the AGB via the BAT output shaft.

The turbine engine of any preceding clause, wherein the driving of the AGB through the BAT output shaft is conducted during operation of the turbine engine.

The turbine engine of any preceding clause, wherein the BAT turbine is directly coupled to the AGB through the BAT output shaft.

The turbine engine of any preceding clause, further comprising a pre-cooler heat exchanger (PCE) fluidly coupled to the fan section and a system external to the turbine engine.

The turbine engine of 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.

The turbine engine of any preceding clause, wherein the third bleed air passage and the bypass passage meet at a junction upstream of the PCE.

The turbine engine of 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 fluidly coupled to the system external the turbine engine to define a fluid output of the PCE.

The turbine engine of any preceding clause, wherein the PCE includes a cooling fluid input and a cooling fluid output, with the cooling fluid input being fluidly coupled to at least one of the fan section or the compressor section.

The turbine engine of any preceding clause, wherein the system external the turbine engine includes an environmental control system.

The turbine engine of any preceding clause, wherein the second bleed air passage and the third bleed air passage each include a respective working fluid with a respective temperature and respective pressure, and the temperature and pressure of the working fluid in the second bleed air passage is less than the temperature and the pressure of the working fluid in the third bleed air passage.

The turbine engine of any preceding clause, wherein the ATS is configured to restart, during a wind down of the turbine engine and through driving of the ATS output shaft, the turbine engine.

The turbine engine of 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 a working fluid within the fourth bleed air passage is supplied to the ATS during restart of the turbine engine.

The turbine engine of any preceding clause, wherein the bleed air circuit comprises a low pressure (LP) bleed air passage, and a high pressure (HP) bleed air passage, with the LP bleed air passage being fluidly coupled to a portion of the turbine engine upstream of the HP bleed air passage.

The turbine engine of 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.

The turbine engine of any preceding clause, wherein the compressor section includes a high pressure (HP) compressor and a low pressure (LP) compressor, 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.

The turbine engine of any preceding clause, further comprising a controller configured to automatically selectively supply a working fluid within 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 the system external the turbine engine.

The turbine engine of 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.

The turbine engine of any preceding clause, further comprising an engine casing housing the engine core, with the BAT and the ATS being provided exterior the engine casing.

The turbine engine of any preceding clause, wherein a driving of the ATS and the BAT both drive the engine drive shaft through the AGB.

The turbine engine of any preceding clause, further comprising a first valve provided along the LP bleed air passage and selectively fluidly coupling a bleed air from the turbine engine to the LP bleed air passage.

The turbine engine of any preceding clause, further comprising a second valve provided along the HP bleed air passage and selectively fluidly coupling a bleed air from the turbine engine to the HP bleed air passage.

The turbine engine of any preceding clause, further comprising a third valve provided along the first bleed air passage, the third valve selectively fluidly coupling a circuit bleed air from the first bleed air passage to the BAT.

The turbine engine of any preceding clause, wherein the third valve is provided at a junction between the first bleed air passage.

The turbine engine of any preceding clause, wherein the third valve selectively fluidly couples a bleed air from the turbine engine to at least one of the bypass passage or the second bleed air passage.

The turbine engine of any preceding clause, further comprising a fourth valve provided along the second bleed air passage.

The turbine engine of any preceding clause, wherein the fourth valve selectively fluidly couples a circuit bleed air from the first bleed air passage to the BAT.

The turbine engine of 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 the external system.

The turbine engine of any preceding clause, wherein the sixth valve is provided downstream the junction between the bypass passage and the third bleed air passage.

The turbine engine of any preceding clause, wherein the sixth valve defines the junction between the bypass passage and the third bleed air passage.

The turbine engine of any preceding clause, further comprising a seventh valve provided along the fourth bleed air passage.

The turbine engine of any preceding clause, wherein the fourth valve selectively fluidly couples a circuit bleed air from at least one of the bypass passage or the third bleed air passage to the ATS.

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

The method of any preceding clause, further comprising driving, through the bleed air supplied to the BAT, the BAT output shaft.

The method of any preceding clause, further comprising driving, at least partially through the BAT output shaft, the engine drive shaft.

The method of any preceding clause, further comprising driving, at least partially through the BAT output shaft, the engine drive shaft during an operation of the turbine engine.

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

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