Abstract: An operating method is provided during which a command is received to decrease thrust generated by a propulsor rotor from a first thrust level to a second thrust level. The propulsor rotor is operatively coupled to an engine core and an electric machine. The engine core includes a flowpath, a compressor section, a combustor section and a turbine section. The engine core is operated in a transient state to decrease total power of the engine core from a first power level to a second power level in response to the command. The electric machine is operated as a generator to reduce power output from the engine core to the propulsor rotor while the engine core is operating in the transient state. A clearance control system for the engine core is operated based on the operation of the electric machine.

Abstract: An operating method is provided during which a command is received to increase thrust generated by a propulsor rotor from a first thrust level to a second thrust level. The propulsor rotor is operatively coupled to an engine core and an electric machine. The engine core includes a flowpath, a compressor section, a combustor section and a turbine section. The engine core is operated in a transient state to increase power output from the engine core to the propulsor rotor from a first power level to a second power level in response to the command. The electric machine is operated to boost the power output from the engine core to the propulsor rotor while the engine core is operating in the transient state. A clearance control system for the engine core is operated based on the operation of the electric machine.

Abstract: A method is provided for an HEP system that includes a gas turbine engine and an electric motor configured to assist the gas turbine engine by rotating a first shaft of the gas turbine engine. The method includes receiving a throttle command, and determining, based on an amount of electric power available to the electric motor, a power allocation between the gas turbine engine and the electric motor for an acceleration period during which a rotational speed of the first shaft is accelerated to implement the throttle command. The method also includes determining a target clearance between a tip of a rotor blade and a case structure for the acceleration period and, during the acceleration period, implementing the power allocation and operating an active clearance control (ACC) system to establish the target clearance. A system for an aircraft and a method for a HEP system are also disclosed.

Abstract: An operating method is provided during which a command is received to decrease thrust generated by a propulsor rotor from a first thrust level to a second thrust level. The propulsor rotor is operatively coupled to an engine core and an electric machine. The engine core includes a flowpath, a compressor section, a combustor section and a turbine section. The engine core is operated in a transient state to decrease total power of the engine core from a first power level to a second power level in response to the command. The electric machine is operated as a generator to reduce power output from the engine core to the propulsor rotor while the engine core is operating in the transient state. A clearance control system for the engine core is operated based on the operation of the electric machine.

Abstract: The present disclosure relates to gas turbine engine and seal configurations, and components for a gas turbine engine. In one embodiment, a seal for a gas turbine engine includes a rotary seal element, the rotary seal element configured to rotate during operation of a gas turbine engine, and a stationary seal element having an annular seal surface. The stationary seal element includes a first area of the annular seal surface configured to engage with the rotary seal element, and the stationary seal element includes a second area of the annular seal surface configured to provide reduced resistance to the rotary seal element during a flight windmilling event.

Abstract: Aspects of the disclosure are directed to an active clearance control system for an engine of an aircraft, comprising: a collector that is configured to receive a cooling fluid, at least two manifolds coupled to the collector, where a first of the manifolds is configured to receive at least a first portion of the cooling fluid from the collector and a second of the manifolds is configured to receive at least a second portion of the cooling fluid from the collector, and an insert coupled to the collector and the manifolds, where the insert is configured to seal an interface between the collector and the at least two manifolds over an operating range of the engine.

Abstract: A fastener assembly for a gas turbine engine, and method of assembly, includes a first body having a first surface and a recess communicating through the first surface. The recess may be defined by a bottom surface and a side face spanning between the first and bottom surfaces. A shank of the assembly is generally engaged between the first body and a second body and includes opposite first and second end portions. The first end portion is located in the recess and the second end portion is engaged to the second body. A filler of the assembly is generally located in the recess to cover the first end portion. To reduce windage, the filler has an outer surface that is substantially flush with the first surface.

Abstract: Aspects of the disclosure are directed to systems and methods for receiving operating state parameters associated with an operative state of an aircraft, determining a clearance value between a first structure of the engine and a second structure of the engine, where the clearance value is determined based on the operating state parameters and a passive clearance model that includes a specification of an uncertainty in the clearance value, determining that the clearance value deviates from a clearance target in an amount that is greater than a threshold, and engaging an active clearance control (ACC) mechanism based on the deviation.

Abstract: Aspects of the disclosure are directed to an active clearance control system for an engine of an aircraft, comprising: a collector that is configured to receive a cooling fluid, at least two manifolds coupled to the collector, where a first of the manifolds is configured to receive at least a first portion of the cooling fluid from the collector and a second of the manifolds is configured to receive at least a second portion of the cooling fluid from the collector, and an insert coupled to the collector and the manifolds, where the insert is configured to seal an interface between the collector and the at least two manifolds over an operating range of the engine.

Abstract: Aspects of the disclosure are directed to systems and methods for receiving operating state parameters associated with an operative state of an aircraft, determining a clearance value between a first structure of the engine and a second structure of the engine, where the clearance value is determined based on the operating state parameters and a passive clearance model that includes a specification of an uncertainty in the clearance value, determining that the clearance value deviates from a clearance target in an amount that is greater than a threshold, and engaging an active clearance control (ACC) mechanism based on the deviation.

Abstract: The present disclosure relates to gas turbine engine and seal configurations, and components for a gas turbine engine. In one embodiment, a seal for a gas turbine engine includes a rotary seal element, the rotary seal element configured to rotate during operation of a gas turbine engine, and a stationary seal element having an annular seal surface. The stationary seal element includes a first area of the annular seal surface configured to engage with the rotary seal element, and the stationary seal element includes a second area of the annular seal surface configured to provide reduced resistance to the rotary seal element during a flight windmilling event.

Abstract: A fastener assembly for a gas turbine engine, and method of assembly, includes a first body having a first surface and a recess communicating through the first surface. The recess may be defined by a bottom surface and a side face spanning between the first and bottom surfaces. A shank of the assembly is generally engaged between the first body and a second body and includes opposite first and second end portions. The first end portion is located in the recess and the second end portion is engaged to the second body. A filler of the assembly is generally located in the recess to cover the first end portion. To reduce windage, the filler has an outer surface that is substantially flush with the first surface.