Abstract: A method for providing overspeed protection for a gas turbine engine having an engine shaft includes monitoring, via an overspeed protection system, a torque of the engine shaft. The method also includes determining, via the overspeed protection system, at least one additional condition of the engine shaft. Further, the method includes determining, via the overspeed protection system, an overspeed condition of the gas turbine engine when the torque of the engine shaft drops below a torque threshold and the at least one additional condition of the engine shaft is indicative of the gas turbine engine being in an operational state. Thus, the overspeed condition is indicative of an above normal rotational speed of the engine shaft. In addition, the method includes initiating a shutdown procedure for the gas turbine engine in response to the determined overspeed condition to reduce the rotational speed of the engine shaft.

Abstract: A gas turbine engine is provided. The gas turbine engine includes: a fan; a turbomachine drivingly coupled to the fan and defining in part a working gas flowpath, the gas turbine engine defining a bypass passage over the turbomachine, the turbomachine defining an annular cooling passage extending between a CP inlet and a CP outlet, the CP inlet in airflow communication with the working gas flowpath and the CP outlet in airflow communication with the bypass passage; and a variable bleed assembly including a variable bleed duct extending between a VB inlet and a VB outlet, the VB inlet in airflow communication with the working gas flowpath at a location downstream of the CP inlet and the VB outlet in airflow communication with the annular cooling passage for urging an airflow through the cooling passage.

Abstract: A gas turbine engine including: a fan assembly comprising a fan; and a turbomachine drivingly coupled to the fan and including a compressor section, a combustion section, and a turbine section arranged in serial flow order and defining in part a working gas flowpath, the gas turbine engine defining a bypass passage over the turbomachine; the turbomachine further including a heat exchanger and defining an annular cooling passage extending between an inlet and an outlet, the inlet in airflow communication with the working gas flowpath at a location upstream of the compressor section and the outlet in airflow communication with the bypass passage, the heat exchanger in thermal communication with an airflow through the cooling passage.

Abstract: A gas turbine engine includes a rotatably driven engine component including a shaft coupling. The shaft coupling defines a first axial centerline and includes an inner surface. The inner surface includes a plurality of internal splines extending radially inwardly from the inner surface with respect to the first axial centerline. The engine further includes a driving member having a driving end portion and defining a second axial centerline. The driving end portion includes an outer surface and a plurality of external splines extending radially outwardly from the outer surface with respect to the second axial centerline. The plurality of external splines is drivingly engaged with the plurality of internal splines. The plurality of internal splines or the plurality of external splines comprises bowed splines.

Abstract: A fuel system is provided for an aircraft having a fuel source. The fuel system includes a fuel oxygen reduction unit defining a liquid fuel supply path, a stripping gas supply path, a liquid fuel outlet path, and a stripping gas return path, wherein the stripping gas return path is in airflow communication with the fuel source.

Abstract: A gas turbine engine having a waste heat recovery system is provided. The gas turbine engine includes a compressor section, a combustion section, a turbine section, and an exhaust section in serial flow order and together defining a core air flowpath, the exhaust section including a primary exhaust flowpath and a waste heat recovery flowpath parallel to the primary exhaust flowpath; and the waste heat recovery system includes a heat source exchanger positioned in thermal communication with a first portion of the waste heat recovery flowpath.

Abstract: The present disclosure is directed to a gas turbine engine defining a radial direction, a longitudinal direction, and a circumferential direction, an upstream end and a downstream end along the longitudinal direction, and an axial centerline extended along the longitudinal direction. The gas turbine engine includes a fan assembly including a plurality of fan blades rotatably coupled to a fan rotor in which the fan blades define a maximum fan diameter and a fan pressure ratio. The gas turbine engine further includes a low pressure (LP) turbine defining a core flowpath therethrough generally along the longitudinal direction. The core flowpath defines a maximum outer flowpath diameter relative to the axial centerline. The gas turbine engine defines a fan to turbine diameter ratio of the maximum fan diameter to the maximum outer flowpath diameter. The fan to turbine diameter ratio over the fan pressure ratio is approximately 0.90 or greater.

Abstract: A gas turbine engine is provided. The gas turbine engine includes a turbomachine defining an engine inlet to an inlet duct, a fan duct inlet to a fan duct, and a core inlet to a core duct; a primary fan driven by the turbomachine; and a secondary fan located downstream of the primary fan within the inlet duct. The gas turbine engine defines a thrust to power airflow ratio between 3.5 and 100 and a core bypass ratio between 0.1 and 10, wherein the thrust to power airflow ratio is a ratio of an airflow through a bypass passage over the turbomachine plus an airflow through the fan duct to an airflow through the core duct, and wherein the core bypass ratio is a ratio of the airflow through the fan duct to the airflow through the core duct.

Abstract: A thermal management system of a gas turbine engine, the thermal management system including: a thermal transport bus configured to have a heat exchange fluid flowing therethrough and including a pump including a plurality of bearings; an auxiliary thermal bus in thermal communication with the plurality of bearings; and an auxiliary heat exchanger in thermal communication with the auxiliary thermal bus.

Abstract: A gas turbine engine includes a fan having a plurality of fan blades, a turbomachine operably coupled to the fan for driving the fan, the turbomachine including a compressor section, a combustion section, and a turbine section in serial flow order and together defining a core air flowpath, a nacelle surrounding and at least partially enclosing the fan, the nacelle defining a longitudinal axis, and an inlet pre-swirl feature located upstream of the plurality of fan blades, the inlet pre-swirl feature attached to or integrated into the nacelle, wherein the inlet pre-swirl feature is transitionable between a first angle with respect to the longitudinal axis of the nacelle and a second angle with respect to the longitudinal axis of the nacelle.

Abstract: A pericritical fluid system for a thermal management system associated with a turbine engine may include one or more sensors configured to generate sensor outputs corresponding to one or more phase properties of a pericritical fluid flowing through a cooling circuit of the thermal management system, and a controller configured to generate control commands configured to control one or more controllable components of the thermal management system based at least in part on the sensor outputs. The one or more sensors may include one or more phase detection sensors, such as an acoustic sensor.

Abstract: A fuel oxygen reduction unit assembly for a fuel system is provided. The fuel oxygen reduction unit assembly includes: a fuel oxygen reduction unit located downstream from the fuel source and defining a stripping gas flowpath and a liquid fuel flowpath, the fuel oxygen reduction unit comprising a means for transferring an amount of oxygen from a liquid fuel flow through the liquid fuel flowpath to a gas flow through the stripping gas flowpath; and an oxygen conversion unit in flow communication with the stripping gas flowpath configured to extract a flow of oxygen from a gas flow through the stripping gas flowpath, the oxygen conversion unit defining an oxygen outlet configured to provide the extracted flow of oxygen to an external system.

Abstract: A turbofan engine is provided. The turbofan engine includes a fan comprising a plurality of fan blades; a turbomachine operably coupled to the fan for driving the fan, the turbomachine comprising a compressor section, a combustion section, and a turbine section in serial flow order and together defining a core air flowpath; a nacelle surrounding and at least partially enclosing the fan; an inlet pre-swirl feature located upstream of the plurality of fan blades, the inlet pre-swirl feature attached to or integrated into the nacelle; and a means for reducing ice buildup or ice formation on the inlet pre-swirl feature, the means in communication with the inlet pre-swirl feature.

Abstract: A fuel delivery system for a gas turbine engine includes a fuel tank; a draw pump downstream of the fuel tank for generating a liquid fuel flow from the fuel tank; a main fuel pump downstream of the draw pump; and a fuel oxygen conversion unit downstream of the draw pump and upstream of the main fuel pump. The fuel oxygen conversion unit includes a stripping gas line; a contactor in fluid communication with the stripping gas line and the draw pump for forming a fuel/gas mixture; and a dual separator pump in fluid communication with the contactor for receiving the fuel/gas mixture and separating the fuel/gas mixture into a stripping gas flow and the liquid fuel flow at a location upstream of the main fuel pump.

Abstract: A fuel oxygen reduction unit for an engine is provided. The fuel oxygen reduction unit includes an inlet fuel line; a stripping gas source; a contactor selectively in fluid communication with the stripping gas source, the inlet fuel line, or both to form a fuel/gas mixture; and a separator that receives the fuel/gas mixture, the separator configured to separate the fuel/gas mixture into an outlet stripping gas flow and an outlet fuel flow; wherein a flow of stripping gas passes through the fuel oxygen reduction unit a single time.

Abstract: A shaft power transfer system includes a first mechanical clutch mechanism operably coupling a high-pressure shaft to a low-pressure shaft. The first mechanical clutch mechanism transfers power from the high-pressure shaft to the low-pressure shaft at a predefined first speed transient condition. The system further includes a second mechanical clutch mechanism that operably couples the low-pressure shaft to the high-pressure shaft. The second mechanical clutch mechanism transfers power from the low-pressure shaft to the high-pressure shaft at a predefined second speed transient condition where the predefined first speed transient condition is different than the predefined second speed transient condition.

Abstract: A method for providing overspeed protection for a gas turbine engine having an engine shaft includes monitoring, via an overspeed protection system, a torque of the engine shaft. The method also includes determining, via the overspeed protection system, at least one additional condition of the engine shaft. Further, the method includes determining, via the overspeed protection system, an overspeed condition of the gas turbine engine when the torque of the engine shaft drops below a torque threshold and the at least one additional condition of the engine shaft is indicative of the gas turbine engine being in an operational state. Thus, the overspeed condition is indicative of an above normal rotational speed of the engine shaft. In addition, the method includes initiating a shutdown procedure for the gas turbine engine in response to the determined overspeed condition to reduce the rotational speed of the engine shaft.

Abstract: An aircraft defining a longitudinal direction and a lateral direction is provided. The aircraft includes: a fuselage; an engine mounted at a location spaced from the fuselage of the aircraft, the engine comprising a plurality of rotor blades; and a fuselage shield attached to or formed integrally with the fuselage at a location in alignment with the plurality of rotor blades along the lateral direction, the fuselage shield comprising a first layer defining a first density and a second layer defining a second density, the first density being different than the second density.

Abstract: A gas turbine engine includes a turbomachine and a thermal management system. The thermal management system includes a heat source heat exchanger configured to collect heat from the turbomachine during operation; a heat sink heat exchanger; and a thermal transport bus having a heat exchange fluid configured to flow therethrough at a pressure within an operational pressure range. The thermal management system defines an operational temperature range for the heat exchange fluid, the operational temperature range having a lower temperature limit less than about zero degrees Fahrenheit at a pressure within the operational pressure range and an upper temperature limit of at least about 1000 degrees Fahrenheit at a pressure within the operational pressure range.

Abstract: A gas turbine engine includes a fan having a plurality of fan blades, a turbomachine operably coupled to the fan for driving the fan, the turbomachine including a compressor section, a combustion section, and a turbine section in serial flow order and together defining a core air flowpath, a nacelle surrounding and at least partially enclosing the fan, the nacelle defining a longitudinal axis, and an inlet pre-swirl feature located upstream of the plurality of fan blades, the inlet pre-swirl feature attached to or integrated into the nacelle, wherein the inlet pre-swirl feature is transitionable between a first angle with respect to the longitudinal axis of the nacelle and a second angle with respect to the longitudinal axis of the nacelle.