TORQUE EXTRACTION SYSTEMS, TURBINE ENGINES, AND METHODS FOR EXTRACTING TORQUE FROM TURBINE ENGINES

A torque extraction system for a turbine engine includes an electric machine coupled to a shaft of the turbine engine by way of a gearbox disposed between the electric machine and the shaft of the turbine engine, and the electric machine draws torque from the shaft and converts the torque to electrical energy. A power bus is electrically coupled to the electric machine and provides power to the electric machine. A sensor senses vibrational forces acting on a rotor of the turbine engine, and a controller electrically coupled to the electric machine receives signals from the sensor corresponding to the sensed vibrational forces. The controller operates the gearbox disposed between the electric machine and the shaft of the turbine engine to increase the torque that the electric machine draws from the shaft when the vibrational forces sensed by the sensor meet or exceed a predetermined threshold.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Indian application No. 202311031037 filed on May 1, 2023, the entire contents of which is hereby incorporated by reference.

TECHNICAL FIELD

The present specification generally relates to turbine engines and, more specifically, to torque extraction systems for turbine engines.

BACKGROUND

During certain operating conditions of a turbine engine, a rotor of the turbine engine may be subjected to a variety of axial loads. For example, at high operating speeds, a substantial axial load may act on the rotor in an aft direction, while the axial load may be diminished and/or reversed at low and idling speeds. As the axial load on the rotor is reduced, vibrational forces are often observed acting on the rotor. Over time, if the vibrational forces continue to act on the rotor, the rotor may experience cycle fatigue, which may lead to degradation of the rotor and/or other components of the turbine engine.

DETAILED DESCRIPTION

Embodiments described herein are directed to turbine engines, torque extraction systems, and methods of extracting torque from a turbine engine. A turbine engine may include a high pressure rotor including a high pressure compressor and high pressure turbine coupled together via a high pressure shaft. The turbine engine may further include a torque extraction system including an electric machine, a gearbox, and a controller having a sensor. The high pressure shaft may connect the torque extraction system to the high pressure rotor, and a sensor of the torque extraction system may be used to track vibrational forces acting on the high pressure rotor. The controller may receive the vibrational forces and monitor the vibrational forces to ensure that the vibrational forces acting on the high pressure rotor remain beneath a predetermined threshold. In the event the vibrational forces acting on the high pressure rotor exceed the predetermined threshold, the electric machine may increase a torque demand on the high pressure shaft to extract torque from the high pressure shaft. As the torque is extracted from the high pressure shaft, axial thrust may be applied to the high pressure rotor in an aft direction, causing the vibrational forces of the high pressure rotor to decrease. Torque may continue to be extracted from the high pressure shaft until the vibrational forces acting on the high pressure rotor drops below the predetermined threshold.

As described herein, a discharge pressure of a turbine engine may vary broadly, such as, for example, a normal operating range of a turbine engine from a low or idling speed to maximum speed of the engine. This variation in operating conditions causes a substantial variation in the axial force exerted on the rotor of a turbine engine. Thus, at certain (e.g., high) operating speeds, there may be a substantial axial load on the rotor in an aft or forward direction. On the other hand, at other (e.g., low or idling) speeds, this axial force on the rotor is substantially reduced and may shift to the opposite direction, resulting in a condition known as crossover, occurring at a time when the force exerted on the rotor changes from an aft direction to a forward direction or vice versa.

During certain engine conditions, vibrational forces may be observed on the rotor of a turbine engine. For example, vibrational forces are typically observed when the axial load on the rotor of the turbine is small, zero, or at the thrust crossover condition, as has been described herein. If left unchecked, the vibrational forces acting on the rotor can result in non-synchronous vibration issues within the turbine engine. Furthermore, rotors that frequently experience vibrational forces may suffer from high cycle fatigue, which may shorten the life cycle of the rotor or other components of the turbine engine. By implementing a torque extraction system in the turbine engine, it may be possible to monitor vibrational forces acting on a rotor during operation of a turbine engine to ensure that the vibrational forces remain below a predetermined threshold in order to reduce or minimize the aforementioned high cycle fatigue. Furthermore, in the event the vibrational forces exceed the predetermined threshold, the torque extraction system may be operable to extract torque from the rotor to bring the vibrational forces below the predetermined threshold, thereby alleviating potential problems arising from non-synchronous vibration and high cycle fatigue.

Various embodiments of turbine engines, torque extraction systems, and methods of extracting torque from a turbine engine are described in more detail herein. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

As used herein, the terms “first,” and “second,” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

The terms “upstream” and “downstream” refer to the relative direction with respect to a flow in a pathway. For example, with respect to a fluid flow, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. However, the terms “upstream” and “downstream” as used herein may also refer to a flow of electricity.

Referring now toFIG.1, a turbine engine100suitably designed to be mounted to a wing or fuselage of an aircraft is depicted. The turbine engine100may include a torque extraction system50. In embodiments, the torque extraction system50may include an electric machine56(e.g., an electric motor or generator), a controller76, and a power bus58. In these embodiments, a plurality of electric lines60may be used to electrically couple the electric machine56to the power bus58. For example, the power bus58may include various switches or other power electronics movable to electrically connect the various components of the turbine engine100. Additionally, the power bus58may further include power electronics, such as inverters, converters, rectifiers, etc., for conditioning or converting electrical power within the turbine engine100.

In these embodiments, the torque extraction system50may monitor nominal transient vibrational forces that occur within the turbine engine100during a particular flight envelope (e.g., takeoff, cruise, descent, landing, etc.) to ensure that the vibrational forces remain below a predetermined threshold. In the event the predetermined threshold is met or exceeded, the electric machine56may extract torque generated by the turbine engine100in order to increase thrust in an aft direction and maintain transient vibrational forces below the predetermined threshold, as will be described in additional detail herein.

Referring still toFIG.1, the turbine engine100may further include a turbomachine102and a prime propulsor, the prime propulsor being a fan (referred to as “fan104” with reference toFIG.1). As stated, the turbine engine100includes the fan104and the turbomachine102disposed downstream (e.g., in the +x direction as depicted in the coordinate axis ofFIG.1) from the fan104. In these embodiments, the turbine engine100may also define an axial direction A1 (extending parallel to a longitudinal centerline C provided for reference) and a radial direction R1.

Referring still toFIG.1, the turbomachine102may include a substantially tubular outer casing106that defines an annular inlet108. The outer casing106encases, in serial flow relationship, a compressor section including a booster or low pressure (LP) compressor110and a high pressure (HP) compressor112; a combustion section114; a turbine section including a first, high pressure (HP) turbine116and a second, low pressure (LP) turbine118; and a jet exhaust nozzle section120. The compressor section, combustion section114, and turbine section together define at least in part a core air flowpath121through the turbomachine102.

The turbomachine102of the turbine engine100additionally includes one or more shafts rotatable with at least a portion of the turbine section and, for the embodiment depicted, at least a portion of the compressor section. More particularly, for the embodiment depicted, the turbine engine100includes a high pressure (HP) shaft122, which drivingly connects the HP turbine116to the HP compressor112. In these embodiments, the HP turbine116, HP compressor112, and HP shaft122may be referred to as a high pressure rotor117. Additionally, the exemplary turbine engine100includes a low pressure (LP) shaft124, which drivingly connects the LP turbine118to the LP compressor110.

Further, the exemplary fan104depicted is configured as a variable pitch fan having a plurality of fan blades128coupled to a disk130in a spaced apart manner. The fan blades128extend outwardly from disk130generally along the radial direction R1. Each fan blade128is rotatable relative to the disk130about a respective pitch axis PI by virtue of the fan blades128being operatively coupled to a suitable actuation member132configured to collectively vary the pitch of the fan blades128. The fan104is mechanically coupled to the LP shaft124, such that the fan104is mechanically driven by the second, LP turbine118.

Referring still to theFIG.1, the disk130is covered by a rotatable front hub136aerodynamically contoured to promote an airflow through the plurality of fan blades128. Additionally, the turbine engine100includes an annular fan casing or outer nacelle138that circumferentially surrounds the fan104and/or at least a portion of the turbomachine102. Accordingly, the exemplary turbine engine100depicted may be referred to as a “ducted” turbofan engine. Moreover, the nacelle138is supported relative to the turbomachine102by a plurality of circumferentially-spaced outlet guide vanes140. A downstream section142of the nacelle138extends over an outer portion of the turbomachine102so as to define a bypass airflow passage144therebetween.

Referring now toFIGS.1and2, an embodiment of the torque extraction system50is depicted. In these embodiments, the electric machine56of the torque extraction system50is positioned within the turbomachine102of the turbine engine100, inward of the core air flowpath121, and is in mechanical communication with one of the systems of the turbomachine102. For example, for the embodiment depicted, the electric machine56is driven by the high pressure rotor117.

More specifically, as shown inFIG.2, the electric machine56may be driven by the HP turbine116(FIG.1) through the HP shaft122. In these embodiments, the electric machine56may be coupled to the HP shaft122through a gearbox134, such as an accessory gearbox, which may include a plurality of gears for adjusting the rotational speed of the HP shaft122. In these embodiments, the gearbox134may transfer rotational power from the HP shaft122to the electric machine56in the form of electrical power. Conversely, the electric machine56may be configured to convert electrical power into mechanical (e.g., rotational) power for the HP shaft122.

Referring stillFIG.2, the torque extraction system50may further include the controller76and a sensor, such as a plurality of sensors74. As should be appreciated, the controller76may be configured to distribute electrical power between the various components of the torque extraction system50. For example, the controller76may be operable with the power bus58(including the one or more switches or other power electronics) to provide electrical power to, or draw electrical power from, the various components, such as the electric machine56and gearbox134, to operate the torque extraction system50between various operating modes and perform various functions. Such is depicted schematically as the electric lines60(FIG.1) of the power bus58extending through the controller76(FIG.1). In these embodiments, the controller76may be an engine controller for the turbine engine100(e.g., a Full Authority Digital Engine Control (FADEC)), an aircraft controller, a controller dedicated to the torque extraction system50, etc.

A controller76may be configured to receive data indicative of various operating conditions and parameters of the torque extraction system50during operation of the turbine engine100(FIG.1). For example, the plurality of sensors74may be configured to sense data indicative of various operating conditions and parameters of various components of the turbine engine100, such as rotational speeds, temperatures, pressures, vibrations, etc. More specifically, however, for the exemplary embodiment depicted inFIG.2, the sensors74may be configured to sense data indicative of one or more parameters of the HP rotor117. For example, the sensors74may be configured to sense data indicative of transient vibrations in the HP rotor117.

Referring particularly to the operation of the controller76, in at least certain embodiments, the controller76can include one or more computing device(s)78. The computing device(s)78can include one or more processor(s)78A and one or more memory device(s)78B. The one or more processor(s)78A can include any suitable processing device, such as a microprocessor, microcontroller, integrated circuit, logic device, and/or other suitable processing device. The one or more memory device(s)78B can include one or more computer-readable media, including, but not limited to, non-transitory computer-readable media, RAM, ROM, hard drives, flash drives, and/or other memory devices.

The one or more memory device(s)78B can store information accessible by the one or more processor(s)78A, including computer-readable instructions78C that can be executed by the one or more processor(s)78A. The instructions78C can be any set of instructions that when executed by the one or more processor(s)78A, cause the one or more processor(s)78A to perform operations. In some embodiments, the instructions78C can be executed by the one or more processor(s)78A to cause the one or more processor(s)78A to perform operations, such as any of the operations and functions for which the controller76and/or the computing device(s)78are configured, the operations for operating the torque extraction system50and/or any other operations or functions of the one or more computing device(s)78. The instructions78C can be software written in any suitable programming language or can be implemented in hardware. Additionally, and/or alternatively, the instructions78C can be executed in logically and/or virtually separate threads on processor(s)78A. The memory device(s)78B can further store data78D that can be accessed by the processor(s)78A. For example, the data78D can include data indicative of power flows, data indicative of turbine engine100operating conditions, data indicative of aircraft operating conditions, and/or any other data and/or information described herein.

The computing device(s)78can also include a communications interface78E used to communicate, for example, with the other components of the turbine engine100(FIG.1), the aircraft incorporating the turbine engine100, the torque extraction system50, etc. For example, in the embodiment depicted, as noted above, the turbine engine100includes one or more sensors74for sensing data indicative of one or more parameters of the turbine engine100and/or the torque extraction system50.

The communications interface78E can include any suitable components for interfacing with one or more network(s), including for example, transmitters, receivers, ports, controllers, antennas, and/or other suitable components. For example, in the embodiment shown, the communications interface78E is configured as a wireless communication network wirelessly in communication with these components

Referring now toFIGS.1and2, in operation, the torque extraction system50may be used to monitor transient vibrational forces acting on the HP rotor117. As has been noted herein, when thrust on the HP rotor117is small, zero, or at the crossover condition (e.g., changing direction from the aft direction to the forward direction), the HP rotor117may experience vibrational forces. In these embodiments, the plurality of sensors74may track the vibrational forces acting on the HP rotor117. The controller76may read the vibrational forces tracked by the plurality of sensors74to determine if the vibrational forces acting on the HP rotor117exceed a predetermined threshold. In the event the vibrational forces exceed the predetermined threshold, the electric machine56may operate gearbox134such that the gearbox134increases the amount of torque (e.g., power) drawn by the electric machine56from the HP shaft122.

As the torque extracted from the HP shaft122by the electric machine56is increased, the axial thrust in the aft direction acting upon the HP rotor117may increase. The increase in axial thrust in the aft direction acting upon the HP rotor117may lead to a decrease in the vibrational forces acting upon the HP rotor117. In these embodiments, the electric machine56may continue to extract additional torque from the HP shaft122until the axial thrust in the aft direction is sufficient to bring the vibrational forces acting on the HP rotor117beneath the predetermined threshold.

Referring now toFIGS.2and3,FIG.3illustrates a flow diagram of a method300of extracting torque from a turbine engine using the torque extraction system50. As depicted inFIG.3, the method300may involve initiating a torque extraction system50of a turbine engine to control electric energy drawn by an electric machine56from a HP shaft122, as shown at block310. For example, to initiate the torque extraction system50, electric power from the power bus58may be provided to the electric machine56and the controller76, such that the electric machine56and controller76may monitor and control torque drawn by the electric machine56from the HP shaft122.

Referring still toFIGS.2and3, the method300may further involve sensing vibrational forces acting on a HP rotor117of the turbine engine using a plurality of sensors74positioned in the torque extraction system50, as is depicted at block320. For example, at least one sensor74may be mounted on the HP rotor117, such that vibrational forces acting on the HP rotor117are similarly transferred to the sensor74, thereby allowing the sensor74to relay the sensed vibrational forces to the controller76.

Turning now to block330, as the plurality of sensors74sense the vibrational forces acting on the HP rotor117, a controller76of the torque extraction system50may monitor the vibrational forces to ensure that the vibrational forces acting on the HP rotor117do not meet or exceed a predetermined threshold. For example, the controller76may continuously receive the vibrational forces sensed by the plurality of sensors74to ensure that the predetermined threshold is not met or exceeded. In these embodiments, the controller76may monitor the vibrational forces acting on the HP rotor117in real time, which may occur simultaneously with the sensing of the vibrational forces by the plurality of sensors74. In the event the vibrational forces acting on the HP rotor117remain below a predetermined threshold, the electric machine56may draw nominal torque from the HP shaft122, as is shown at block340.

However, in the event the vibrational forces acting on the HP rotor117meet and/or exceed the predetermined threshold, the controller76may operably increase the torque drawn by the electric machine56from the HP shaft122, as shown at block350. In these embodiments, the increased torque drawn by the electric machine56from the HP shaft122may be greater than the nominal torque drawn by the electric machine56from the HP shaft122. As the increased torque is drawn by the electric machine56from the HP shaft122, axial thrust acting on the HP rotor117may similarly increase, as shown at block360. In these embodiments, the torque drawn by the electric machine56from the HP shaft122may be continually increased until the controller76determines that the vibrational forces acting on the HP rotor117have fallen beneath the predetermined threshold. Once the vibrational forces acting on the HP rotor117have fallen beneath the predetermined threshold, the controller76may operably decrease the torque drawn by the electric machine56from the HP shaft122, such that the torque drawn by the electric machine56from the HP shaft122returns to the nominal torque.

Referring now toFIG.4, illustrated is a torque extraction system50′ according to another embodiment and suitable for use in the turbine engine100ofFIG.1. The torque extraction system50′ is similar to the torque extraction system50ofFIGS.1-3, therefore, like parts will be identified with like numerals, with it being understood that the description of the like parts of the torque extraction system50applies to the torque extraction system50′ unless otherwise noted. As illustrated inFIG.4, in some embodiments, the torque extraction system50′ may further include an electric energy storage unit55. In these embodiments, the electric energy storage unit55may be configured as one or more batteries, such as one or more lithium-ion batteries, or alternatively may be configured as any other suitable electrical energy storage devices. As will be appreciated, the electric energy storage unit55may be configured, in certain operating conditions, to receive electrical power from the electric machine, and may further be configured in certain operating conditions to provide stored electrical power to the torque extraction system50′ and/or other components of the turbine engine.

In the embodiment depicted inFIG.4, the electric energy storage unit55may be electrically coupled to the electric machine56by way of the power bus58, such that electrical energy drawn by the electric machine56is transferred to the electric energy storage unit55. In these embodiments, when the electric machine56draws excess torque from the HP shaft122, the excess torque may be transferred from the electric machine56to the electric energy storage unit55in the form of electrical energy.

For example, as described herein, the controller76of the torque extraction system50may increase the torque drawn by the electric machine56from the HP shaft122when the controller determines that vibrational forces acting upon the HP rotor117have exceeded the predetermined threshold. In some embodiments, the increased torque drawn by the electric machine56from the HP shaft122may be greater than the torque required to diminish the vibrational forces acting on the HP rotor117beneath the predetermined threshold. In these embodiments, the excess torque may be transferred from the electric machine56to the electric energy storage unit55in the form of the electrical power. The electrical power may then be stored in the electric energy storage unit55and used to charge additional on-board batteries54on the aircraft and/or run additional electric equipment.

Referring now toFIGS.4and5,FIG.5illustrates a flow diagram of a method500of extracting torque from a turbine engine using the torque extraction system50′. As depicted inFIG.5, the method500may involve initiating a torque extraction system50′ of a turbine engine to control electric energy drawn by an electric machine56from a HP shaft122, as shown at block510. For example, to initiate the torque extraction system50′, electric power from the power bus58may be provided to the electric machine56and the controller76, such that the electric machine56and controller76may monitor and control torque drawn by the electric machine56from the HP shaft122.

Referring still toFIGS.4and5, the method may further involve sensing vibrational forces acting on a HP rotor117of the turbine engine using a plurality of sensors74positioned in the torque extraction system50′, as is depicted at block520. For example, at least one sensor74may be mounted on the HP rotor117, such that vibrational forces acting on the HP rotor117are similarly transferred to the sensor74, thereby allowing the sensor74to relay the sensed vibrational forces to the controller76.

Turning now to block530, as the plurality of sensors74sense the vibrational forces acting on the HP rotor117, a controller76of the torque extraction system50′ may monitor the vibrational forces to ensure that the vibrational forces acting on the HP rotor117do not meet or exceed a predetermined threshold. For example, the controller76may continuously receive the vibrational forces sensed by the plurality of sensors74to ensure that the predetermined threshold is not met or exceeded. In these embodiments, the controller76may monitor the vibrational forces acting on the HP rotor117in real time, which may occur simultaneously with the sensing of the vibrational forces by the plurality of sensors74. In the event the vibrational forces acting on the HP rotor117remain below the predetermined threshold, the electric machine56may draw nominal torque from the HP shaft122, as is shown at block540.

However, in the event the vibrational forces acting on the HP rotor117meet and/or exceed the predetermined threshold, the controller76may operably increase the torque drawn by the electric machine56from the HP shaft122, as shown at block550. In these embodiments, the increased torque drawn by the electric machine56from the HP shaft122may be greater than the nominal torque drawn by the electric machine56from the HP shaft122. As the increased torque is drawn by the electric machine56from the HP shaft122, axial thrust acting on the HP rotor117may similarly increase, as shown at block560. In these embodiments, the torque drawn by the electric machine56from the HP shaft122may be continually increased until the controller76determines that the vibrational forces acting on the HP rotor117have fallen beneath the predetermined threshold. Once the vibrational forces acting on the HP rotor117have fallen beneath the predetermined threshold, the controller76may operably decrease the torque drawn by the electric machine56from the HP shaft122, such that the torque drawn by the electric machine56from the HP shaft122returns to the nominal torque.

Referring still toFIGS.4and5, in some embodiments, the method step of increasing the torque drawn by the electric machine56from the HP shaft122may result in excess torque being drawn into the electric machine56. For example, the increased torque drawn by the electric machine56may be greater than the torque required to diminish the vibrational forces acting on the HP rotor117, such that the vibrational forces acting on the HP rotor117drop beneath the predetermined threshold. In these embodiments, the excess torque generated by the electric machine56may be converted to electrical energy and transferred to an electric energy storage unit55, as depicted at block570. The electrical energy transferred to the electric energy storage unit55may then be utilized to power other electric equipment within the turbine engine and/or onboard the aircraft. In these embodiments, it should be understood that the method step of transferring excess torque from the electric machine56to the electric storage unit55may occur simultaneously with the method step of increasing the torque drawn by the electric machine56from the HP shaft122.

Turning now toFIG.6, illustrated is a torque extraction system50″ according to another embodiment and suitable for use in the turbine engine100ofFIG.1. The torque extraction system50″ is similar to the torque extraction system50ofFIGS.1-3and50′ ofFIGS.4-5, therefore, like parts will be identified with like numerals, with it being understood that the description of the like parts of the torque extraction system50,50′ applies to the torque extraction system50″ unless otherwise noted. As illustrated inFIG.6in some embodiments, the electric machine56of the torque extraction system50may further include a clutch53. In some embodiments, the clutch53may be engaged to a turbine starter system, while in other embodiments, the clutch53may act as a mechanical and/or hydraulic braking device coupled to the gearbox134. As depicted inFIG.6, the clutch53may be disposed between the electric machine56and the gearbox134, such that the clutch53may limit interaction between the electric machine56and the gearbox134, as will be described in additional detail herein.

Referring still toFIG.6, in these embodiments, the clutch53may be moved between an engaged position, wherein torque may be transmitted across the clutch53from the HP shaft122to the electric machine56, and a disengaged position, wherein torque may not be transmitted across the clutch53along the HP shaft122to the electric machine56. In such a manner, the clutch53may facilitate operation of the torque extraction system50″ without rotating the HP rotor117. Such may be beneficial, particularly during certain ground operations wherein it may be desirable to rotate the turbomachine102without creating thrust from the HP rotor117.

In at least some aspects, the clutch53may be a two-stage clutch for transitioning from the disengaged position to the engaged position. For example, such a configuration may allow for operation of the torque extraction system50″ during, e.g., idle and post-landing operations, without engaging in rotating the HP rotor117. In such a manner, the electric machine56may be sized to accept 100% of a rated engine power, such that the torque extraction system50may be operated at a rated engine power without engaging the HP rotor117(e.g., by moving the clutch53to the engaged position) and having the electric machine56convert substantially all of such power to electrical energy to be provided to the aircraft, to one or more energy storage units within or in electrical communication with the aircraft, to assist with starting additional engines, a combination thereof, etc.

Referring still toFIG.6, it should be understood that, in these embodiments, the controller76may be configured to receive data indicative of an engagement status of the clutch (e.g., whether the clutch is in the engaged position or the disengaged position). For example, in some embodiment, the clutch53may be configured to transmit a signal to the controller76which indicates the engagement status of the clutch53. In other embodiments, the controller76may further include a clutch sensor which senses the engagement status of the clutch53and relays the status to the controller76. In these embodiments, the controller76may be further operable to actuate the clutch53between the engaged position and the disengaged position in response to the determining that the vibrational forces tracked by the plurality of sensors74exceed the predetermined threshold.

Turning now toFIGS.6and7,FIG.7illustrates a flow diagram of a method700of extracting torque from a turbine engine using the torque extraction system50″ is depicted. As depicted inFIG.7, the method700may involve initiating a torque extraction system50″ of a turbine engine to control electric energy drawn by an electric machine56from a HP shaft122, as shown at block710. For example, to initiate the torque extraction system50″, electric power from the power bus58may be provided to the electric machine56and the controller76, such that the electric machine56and controller76may monitor and control torque drawn by the electric machine56from the HP shaft122.

Referring still toFIGS.6and7, in these embodiments, the torque extraction system50″ may further include a clutch53which may be actuatable between an engaged position, in which torque may be transmitted across the clutch53from the HP shaft122to the electric machine56, and a disengaged position, wherein torque may not be transmitted across the clutch53along the HP shaft122to the electric machine56.

In these embodiments, the method700may further involve sensing vibrational forces acting on a HP rotor117of the turbine engine using a plurality of sensors74positioned in the torque extraction system50″, as is depicted at block720. For example, at least one sensor74may be mounted on the HP rotor117, such that vibrational forces acting on the HP rotor117are similarly transferred to the sensor74, thereby allowing the sensor74to relay the sensed vibrational forces to the controller76.

Turning now to block730, as the plurality of sensors74track the vibrational forces acting on the HP rotor117, a controller76of the torque extraction system may monitor the vibrational forces to ensure that the vibrational forces acting on the HP rotor117do not meet or exceed a predetermined threshold. For example, the controller76may continuously receive the vibrational forces sensed by the plurality of sensors74to ensure that the predetermined threshold is not met or exceeded. In these embodiments, the controller76may monitor the vibrational forces acting on the HP rotor117in real time, which may occur simultaneously with the sensing of the vibrational forces by the plurality of sensors74. In the event the vibrational forces acting on the HP rotor117remain below a predetermined threshold, the clutch53may be positioned in the disengaged position, such that torque does not pass from the HP shaft122to the electric machine56.

However, in the event the vibrational forces acting on the HP rotor117meet and/or exceed the predetermined threshold, the controller76may transition the clutch53from the disengaged position to the engaged position, such that torque is drawn by the electric machine56from the HP shaft122, as shown at block750. In these embodiments, as torque is drawn by the electric machine56from the HP shaft122, axial thrust acting on the HP rotor117may increase, as shown at block760. In these embodiments, the torque drawn by the electric machine56from the HP shaft122may be continually increased until the controller76determines that the vibrational forces acting on the HP rotor117have fallen beneath the predetermined threshold. Once the vibrational forces acting on the HP rotor117have dropped beneath the predetermined threshold, the controller76may further transition the clutch53back to the disengaged position, such that torque is not continually drawn by the electric machine56from the HP shaft122.

Referring still toFIG.7, in some embodiments, the method step of increasing the torque drawn by the electric machine56from the HP shaft122may result in excess torque being drawn into the electric machine56. For example, the increased torque drawn by the electric machine56may be greater than the torque required to diminish the vibrational forces acting on the HP rotor117, such that the vibrational forces acting on the HP rotor117drop below the predetermined threshold. In these embodiments, the excess torque generated by the electric machine56may be converted to electrical energy and transferred to an electric energy storage unit55as described above with respect toFIGS.4and5. The electrical energy transferred to the electric energy storage unit55may then be utilized to power other electric equipment within the turbine engine and/or onboard the aircraft. In these embodiments, it should be understood that the method step of transferring excess torque from the electric machine56to the electric storage unit55may occur simultaneously with the method step of increasing the torque drawn by the electric machine56from the HP shaft122.

In view of the above, it should now be understood that at least some embodiments of the present disclosure are directed to a torque extraction system for a turbine engine. During certain turbine engine conditions, vibrational forces may be observed on a rotor of the turbine engine. For example, vibrational forces are typically observed when the axial load on the rotor of the turbine engine is small, zero, or at the thrust crossover condition. If left unchecked, the vibrational forces acting on the rotor can result in non-synchronous vibration issues within the turbine engine. Furthermore, rotors that frequently experience vibrational forces may suffer from high cycle fatigue, which may shorten the life cycle of the rotor or other components of the turbine engine. By implementing a torque extraction system in the turbine engine, it may be possible to monitor vibrational forces acting on a rotor during operation of a turbine engine to ensure that the vibrational forces remain below a predetermined threshold in order to reduce or minimize the aforementioned high cycle fatigue. Furthermore, in the event the vibrational forces exceed the predetermined threshold, the torque extraction system may be operable to extract torque from the rotor to bring the vibrational forces below the predetermined threshold, thereby alleviating potential problems arising from non-synchronous vibration and high cycle fatigue.

A torque extraction system for a turbine engine, comprising: an electric machine coupled to a shaft of the turbine engine by way of a gearbox disposed between the electric machine and the shaft of the turbine engine, such that the electric machine draws torque from the shaft and converts the torque to electrical energy; a power bus electrically coupled to the electric machine, the power bus providing power to the electric machine; a sensor that senses vibrational forces acting on a rotor of the turbine engine; and a controller electrically coupled to the electric machine, the controller receiving signals from the sensor corresponding to the sensed vibrational forces and operating the gearbox disposed between the electric machine and the shaft of the turbine engine to increase the torque that the electric machine draws from the shaft when the vibrational forces sensed by the sensor meet or exceed a predetermined threshold.

The torque extraction system of the preceding clause, wherein the gearbox is operable to adjust a rotational speed of the shaft.

The torque extraction system of any preceding clause, wherein the controller operates the gearbox to increase the torque that the electric machine draws from the shaft by directing the gearbox to adjust the rotational speed of the shaft.

The torque extraction system of any preceding clause, wherein the shaft is a high-pressure shaft and the rotor is a high-pressure rotor.

The torque extraction system of any preceding clause, wherein the controller is a full authority digital engine control controller (FADEC).

The torque extraction system of any preceding clause, further comprising an electric energy storage unit electrically coupled to the electric machine, wherein the electric machine utilizes the power bus to convert excess torque drawn by the electric machine from the shaft to electric energy that is stored in the electric energy storage unit.

The torque extraction system of any preceding clause, wherein the electrical energy stored by the electric energy storage unit is stored in on-board batteries on an aircraft.

The torque extraction system of any preceding clause, wherein the electric machine further includes a clutch coupling the electric machine to the gearbox, the clutch being transitionable between an engaged position and a disengaged position.

The torque extraction system of any preceding clause, wherein the clutch allows the torque to be transmitted across the clutch from the HP shaft to the electric machine in the engaged position, and prevents the torque from being transmitted across the clutch in the disengaged position.

The torque extraction system of any preceding clause, wherein the controller is further configured to transition the clutch coupling the electric machine to the gearbox from the disengaged position to the engaged position when the vibrational forces acting on the rotor increase meet or exceed the predetermined threshold.

A turbine engine, comprising: a turbomachine, the turbomachine comprising: a rotor comprising a turbine, a compressor, and a shaft that drivingly connects the turbine and the compressor; and a torque extraction system comprising: an electric machine coupled to the shaft of the turbomachine by way of a gearbox disposed between the electric machine and the shaft, such that the electric machine draws torque from the shaft as electrical power; a power bus electrically coupled to the electric machine, such that the power bus provides power to the electric machine; a sensor that senses vibrational forces acting on the rotor of the turbomachine; and a controller electrically coupled to the electric machine, the controller receiving signals from the sensor corresponding to the sensed vibrational forces and operates the gearbox disposed between the electric machine and the shaft of the turbine engine to increase the torque that the electric machine draws from the shaft when the vibrational forces sensed by the sensor meet or exceed a predetermined threshold.

The turbine engine of any preceding clause, wherein the gearbox is operable to adjust a rotational speed of the shaft.

The turbine engine of any preceding clause, wherein the controller operates the gearbox to increase the torque that the electric machine draws from the shaft by directing the gearbox to adjust the rotational speed of the shaft.

The turbine engine of any preceding clause, wherein the controller is a full authority digital engine control controller (FADEC).

The torque extraction system of any preceding clause, further comprising an electric energy storage unit electrically coupled to the electric machine, wherein the electric machine utilizes the power bus to convert excess torque drawn by the electric machine from the shaft to electric energy that is stored in the electric energy storage unit.

The turbine engine of any preceding clause, wherein the electric machine further includes a clutch coupling the electric machine to the gearbox, the clutch being transitionable between an engaged position and a disengaged position.

A method for extracting torque from a turbine engine, the method comprising: initiating, using a controller, a torque extraction system of the turbine engine, the torque extraction system including an electric machine that draws torque from a shaft of the turbine engine; initiating, using the controller, the electric machine, such that the electric machine draws a nominal torque from the shaft of the turbine engine; tracking, using the controller, vibrational forces acting on a rotor of the turbine engine using a plurality of sensors positioned in the torque extraction system; monitoring, using the controller, the vibrational forces acting on the rotor to ensure the vibrational forces acting on the rotor remain below a predetermined threshold; increasing, using the controller, the torque drawn by the electric machine from the shaft of the turbine engine when the vibrational forces acting on the rotor meet or exceed the predetermined threshold; and returning, using the controller, the torque drawn by the electric machine from the shaft of the turbine engine to the nominal torque when the vibrational forces acting on the rotor fall below the predetermined threshold.

The method of any preceding clause, further comprising storing excess torque drawn by the electric machine from the shaft in an electric energy storage unit as electrical energy.

The method of any preceding clause, further comprising providing the electrical energy stored in the electric energy storage unit to the turbine engine.

The method of any preceding clause, wherein the electric machine further comprises a clutch, and the method increasing the torque drawn by the electric machine involves transitioning the clutch from a disengaged position to an engaged position.

The method of any preceding clause, wherein the method step of returning the torque drawn by the electric machine from the shaft to the nominal torque involves transitioning the clutch from the engaged position to the disengaged position.

The method of any preceding clause, wherein the method step of increasing the torque drawn by the electric machine from the shaft further involves increasing an axial thrust on the rotor in an aft direction.