Abstract: A gas turbine engine includes a first spool associated with a primary combustor, a second spool associated with a secondary combustor, and a third spool, each spool including a compressor and a turbine mounted to a shaft. A transmission and accessory gearing are enclosed within an housing of an accessory gearbox. The transmission rotationally couples the third spool to the second spool and accessory gearing. A method of operating the gas turbine engine includes supplying a first fuel flow rate to the primary combustor and supplying a second fuel flow rate to the secondary combustor within an intermediate speed range of the gas turbine engine.

Abstract: A gas turbine engine includes a first spool, a second spool, a third spool, and a epicyclic differential. The epicyclic differential includes a sun gear, planet gears supported from a planet carrier, a ring gear, and a locking member, each housed within an accessory gearbox. The planet carrier couples to the second spool. The sun gear couples to the third spool, and the ring gear couples to engine accessories. A method of operating the gas turbine engine includes supplying a first fuel flow rate to a primary combustor associated with the first and third spools and supplying a second fuel flow rate to a secondary combustor associated with the second spool based on a power lever angle within an intermediate power level range.

Abstract: An aircraft system is provided that includes a first gas turbine engine, a propulsor rotor, a second gas turbine engine, an electric generator and an electric component. The first gas turbine engine includes a first compressor section, a first combustor section, a first turbine section and a first flowpath. The propulsor rotor is rotatably driven by the first gas turbine engine. The second gas turbine engine includes a second compressor section, a second combustor section, a second turbine section and a second flowpath between a second inlet and a second exhaust. The second inlet and the second exhaust are each fluidly coupled with the first flowpath upstream of a combustor of the first combustor section. The electric generator is rotatably driven by the second gas turbine engine. The electric component receives electricity generated by the electric generator. The electric component is discrete from the first gas turbine engine.

Abstract: A power extraction system for a gas turbine engine may comprise a low spool transmission and a low spool accessory gearbox. The low spool accessory gearbox may comprise a generator and a dual clutch transmission. The dual clutch transmission may be coupled between the low spool transmission and the generator.

Abstract: A gas turbine engine includes a first spool associated with a primary combustor, a second spool associated with a secondary combustor, and a third spool, each spool including a compressor and a turbine mounted to a shaft. A transmission and accessory gearing are enclosed within an housing of an accessory gearbox. The transmission rotationally couples the third spool to the second spool and accessory gearing. A method of operating the gas turbine engine includes supplying a first fuel flow rate to the primary combustor and supplying a second fuel flow rate to the secondary combustor within an intermediate speed range of the gas turbine engine.

Abstract: A gas turbine engine includes a first spool, a second spool, a third spool, and a epicyclic differential. The epicyclic differential includes a sun gear, planet gears supported from a planet carrier, a ring gear, and a locking member, each housed within an accessory gearbox. The planet carrier couples to the second spool. The sun gear couples to the third spool, and the ring gear couples to engine accessories. A method of operating the gas turbine engine includes supplying a first fuel flow rate to a primary combustor associated with the first and third spools and supplying a second fuel flow rate to a secondary combustor associated with the second spool based on a power lever angle within an intermediate power level range.

Abstract: A gas turbine engine includes a high speed turbine and a high speed compressor connected by a high speed shaft to define a high speed spool. A low speed turbine and a low speed compressor are connected by a low speed shaft to define a low speed spool. A high speed tower shaft is driven by the high speed spool and a low speed tower shaft is driven by the low speed spool. The low speed tower shaft drives a low speed input gear in an accessory drive differential. The high speed tower shaft drives a high speed input gear in the accessory drive differential. One of the high speed input gear and the low speed input gear increases an output speed of an output gear, and the other decreases an output speed of the output gear. The output gear drives at least one accessory for the gas turbine engine.

Abstract: A gas turbine engine includes a first spool associated with a diffuser and a primary combustor and a second spool associated with a secondary combustor. The first spool includes a first compressor and a first turbine mounted to a first shaft, and the second spool includes a second compressor and a second turbine mounted to a second shaft. An inlet duct fluidly connects the diffuser to the second compressor. An outlet duct assembly fluidly connects the second turbine to the diffuser and the primary combustor.

Abstract: A gas turbine engine includes a first spool rotationally coupled to a plurality of accessories via a first gearing and a second spool rotationally coupled to a third spool via a second gearing. The first gearing and the second gearing rotate independently and are enclosed within a housing of an accessory gearbox. A method of operating the gas turbine engine includes supplying a first fuel flow rate to a primary combustor associated with the first and third spools and supply a second fuel flow rate a secondary combustor associated with the second spool based on a power lever angle within an intermediate power level range.

Abstract: Techniques for determining a fan spool speed value associated with a hybrid electric gas engine (“engine”) are described herein. For example, a method includes generating a first fan spool speed value based on a base extraction amount. The method further includes generating a change in the first fan spool speed value based on a flight condition and a change in extraction amount. The method further includes generating a second fan spool speed value based on the extraction amount and an augmentation value for intersection of a combustion instability and burner pressure limit. The method further includes generating a second change in the second fan spool speed value based on the flight condition and the change in extraction amount. The method further includes determining a final fan spool speed value and operating the engine at the final fan spool speed value.

Abstract: A gas turbine engine includes a first spool of a primary flow path and a second spool of a secondary flow path. The second spool is nonconcentric with the first spool. The second spool includes a boost compressor and a load compressor in fluid communication with an inlet plenum. An inlet duct assembly and an outlet duct assembly place the secondary flow path in communication with the primary flow path. The gas turbine includes a controller operable to vary open areas of variable inlet guide vanes to control a flow division between the boost compressor and the load compressor.

Abstract: A fluid injection system for a gas turbine engine may comprise a fluid injector configured to inject a fluid into an exhaust flow exiting a turbine section of the gas turbine engine. The fluid injector may be coupled to a turbine exit guide vane located at a forward end of an exhaust system of the gas turbine engine. The fluid may decrease a temperature of the exhaust flow exiting the turbine section and/or increase a thrust of the gas turbine engine.

Abstract: A gas turbine engine includes a core flowpath for flowing a core stream, a second flowpath located radially outward from the core flowpath for flowing a second stream, and an auxiliary flowpath located radially outward from the second flowpath for flowing an auxiliary stream. A heat exchanging device is constructed and arranged to divert a portion of the second stream into the auxiliary flowpath. A turbine exhaust case is constructed and arranged to flow the auxiliary stream into the core flowpath for mixing with the core stream.

Abstract: A gas turbine engine includes an inner annular combustor radially inboard of an outer annular combustor. An outer variable turbine vane array is downstream of the outer annular combustor and an inner variable turbine vane array downstream of the inner annular combustor.

Abstract: A hybrid gas turbine engine comprises a turbine, a compressor, and a gear system that is driven by the turbine where the gear system includes a sun gear, a ring gear and a plurality of planet gears, where the ring gear has a ring gear radius of RRing gear and the sun gear has a sun gear radius of RSun gear such that the gear system provides a reduction ratio of RRing gear/RSun gear. A fan is driven by the ring gear, and a generator is driven by the ring gear and provides a generator output signal. A power circuit receives the generator output signal and provides a gain RRing gear/RSun gear to the generator output signal and provides a gain signal indicative thereof to an electrical load.

Abstract: A fluid injection system for a gas turbine engine may comprise a fluid injector configured to inject a fluid into an exhaust flow exiting a turbine section of the gas turbine engine. The fluid injector may be coupled to a turbine exit guide vane located at a forward end of an exhaust system of the gas turbine engine. The fluid may decrease a temperature of the exhaust flow exiting the turbine section and/or increase a thrust of the gas turbine engine.

Abstract: A hybrid gas turbine engine comprises a turbine, a compressor, and a gear system that is driven by the turbine where the gear system includes a sun gear, a ring gear and a plurality of planet gears, where the ring gear has a ring gear radius of RRing gear and the sun gear has a sun gear radius of RSun gear such that the gear system provides a reduction ratio of RRing gear/RSun gear. A fan is driven by the ring gear, and a generator is driven by the ring gear and provides a generator output signal. A power circuit receives the generator output signal and provides a gain RRing gear/RSun gear to the generator output signal and provides a gain signal indicative thereof to an electrical load.

Abstract: A gas turbine engine includes an inner annular combustor radially inboard of an outer annular combustor. An outer variable turbine vane array is downstream of the outer annular combustor and an inner variable turbine vane array downstream of the inner annular combustor.

Abstract: A gas turbine engine includes an outer case structure around a central longitudinal engine axis. An intermediate case structure is included inboard of the outer case structure. An inner case structure is included inboard of the intermediate case structure. A variable area exhaust mixer is included, which is movable between a closed position adjacent to the intermediate case structure and an open position adjacent to the inner case structure.

Abstract: A turbine engine is provided that includes a turbo-compressor, a combustor section, a flow path and a recuperator. The turbo-compressor includes a compressor section and a turbine section. The combustor section includes a combustor and a plenum adjacent the combustor. The flow path extends through the compressor section, the combustor section and the turbine section. The recuperator is configured with the flowpath between the combustor section and the turbine section. An inlet duct to the recuperator is fluidly coupled with the flow path upstream of the plenum. An outlet duct from the recuperator is fluidly coupled with the plenum.