Abstract: A gas turbine engine includes a fan section having a plurality of fan blades, the fan section configured to generate an airflow through the gas turbine engine, an airflow passage having a core passage and a bypass passage separate from the core passage, a low-speed shaft coupled to and configured to rotate the plurality of fan blades, and a sensor assembly coupled to the gas turbine engine and configured to detect torsional vibration in the low-speed shaft. The sensor assembly includes a plurality of dynamic pressure sensors in the airflow passage. The plurality of dynamic pressure sensors detect a dynamic pressure of the airflow passage that is indicative of the torsional vibration in the low-speed shaft. A damping system is configured to dampen the torsional vibration in the low-speed shaft based on a correlation of a measured torsional vibration and an experimental torsional vibration.

Abstract: A gas turbine engine including a frame, a plurality of fan blades configured to rotate about a longitudinal centerline axis of the gas turbine engine, and a mounting assembly coupling the frame to a structure. The gas turbine engine includes a sensor assembly coupled to the mounting assembly and having at least one sensor configured to detect a loading on the mounting assembly and to take a corrective action when propeller whirl is detected above a predetermined limit, and a feature configured to take a corrective action when propeller whirl is detected above a predetermined limit.

Abstract: Methods, apparatus, systems and articles of manufacture are disclosed. An apparatus for mounting a gas turbine engine to a pylon includes: a thrust link coupled to the gas turbine engine and an aft mount, the gas turbine engine coupled to the pylon via a forward mount and the aft mount, a bending restraint having a first end and a second end, the bending restraint including an actuator positioned at the first end to apply a force to a fan section of the gas turbine engine, a first joint positioned at the first end of the bending restraint, the first joint coupled to the first end of the bending restraint and the fan section, and a second joint positioned at the second end of the bending restraint, the second joint coupled to the second end of the bending restraint.

Abstract: A gas turbine engine includes a compressor rotor shaft assembly, an accessory gearbox, and a bowed-rotor mitigation drive device drivingly coupled with the accessory gearbox. The bowed-rotor mitigation drive device is driven during an engine startup phase so as to induce a mechanical load (mechanical energy) to the bowed-rotor mitigation drive device. The mechanical load (mechanical energy) is retained within the bowed-rotor mitigation drive device during operation of the gas turbine engine. The mechanical load (mechanical energy) retained within the bowed-rotor mitigation drive device is periodically released by the bowed-rotor mitigation drive device in a plurality of periods so as to provide, in each period, a driving force to the accessory gearbox, which provides the driving force to the compressor rotor shaft assembly to periodically rotate the compressor rotor shaft assembly.

Abstract: A gas turbine engine includes a compressor section having rotor shaft assembly and a stator shroud assembly including a stator shroud casing surrounding the compressor rotor shaft assembly, a compressor flow passage being defined between the compressor rotor shaft assembly and the stator shroud casing. A compressor bleed air system includes a compressor bleed air duct that includes a sloped inlet portion, such as a NACA submerged inlet portion, in the stator shroud casing. Alternatively, stator vanes at a compressor bleed air passage may have a NACA inlet scoop and an airflow passage through the stator vane providing a bleed airflow to a cavity, which has airflow passages providing bleed air to an upstream side of the bleed air passage.

Abstract: 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.

Abstract: Clearance control systems with thermal actuators are disclosed. An example thermally-actuated clearance control system for a gas turbine engine includes a compliant material; a high-conductive material coupled to a first surface of the compliant material, the high-conductive material thermally coupling the compliant material to a heated substance, the compliant material to expand radially-inward toward a fan blade when the high-conductive material provides heat; and an abradable material coupled to a second surface of the compliant material facing the fan blade.

Abstract: A gas turbine engine includes a compressor with an inner casing and an outer casing. The inner casing defines a primary flow path for airflow through the compressor, the inner casing and the outer casing define a bleed air cavity therebetween. The inner casing at least partially defines a first bleed air channel between the primary flow path and the first bleed air cavity. The first bleed air channel is defined between a first wall and a second wall, wherein the first wall is upstream from the second wall. The first wall includes a plurality of holes in fluid communication with the primary flow path and fluidly coupled to a suction manifold. The plurality of holes is configured to energize a fluid boundary layer along the first wall.

Abstract: A cooling system for a turbine engine. The turbine engine includes a compressor, a turbine, and a shaft that drivingly couples the compressor and the turbine. The cooling system includes one or more cavities of the compressor. The cooling system includes a shaft flowpath defined in the shaft. The shaft includes one or more shaft apertures that provide fluid communication between the shaft flowpath and the one or more cavities. Air passes through the one or more shaft apertures and the shaft flowpath during a shutdown of the turbine engine to cool the one or more cavities.

Abstract: A turbomachine including a turbine rotor, a compressor rotor, and a shaft, and at least one balance weight assembly connected to the shaft. The shaft drivingly connects the turbine rotor with the compressor rotor to rotate the compressor rotor about a rotational axis when the turbine rotor rotates about the rotational axis. The at least one balance weight assembly including a first chamber, at least one additional chamber, and a balance weight movable between the first chamber and the at least one additional chamber.

Abstract: Systems and methods for optimizing clearances within an engine include an adjustable coupling configured to couple a thrust link to the aircraft engine, an actuator coupled to the adjustable coupling, where motion produced by the actuator adjusts a hinge point of the adjustable coupling, sensors configured to capture real time flight data, and an electronic control unit. The electronic control unit receives flight data from the sensors, implements a machine learning model trained to predict clearance values within the engine based on the received flight data, predicts, with the machine learning model, the clearance values within the engine based on the received flight data, determines an actuator position based on the clearance values, and causes the actuator to adjust to the determined actuator position.

Abstract: A method for cooling a compressor section of a gas turbine engine includes sensing, via at least one first temperature sensor, a first temperature at the first location on a stationary assembly of the compressor section. The method also includes sensing, via at least one second temperature sensor, a second temperature at a second location on the stationary assembly of the compressor section. The second location is spaced apart from the first location. The method also includes determining, via a controller, a delta between the first temperature and the second temperature. Further, the method includes operating, via the controller, at least one cooling element when the delta exceeds a predetermined threshold, the at least one cooling element provided at the first location of the stationary assembly of the compressor section.

Abstract: A gas turbine engine including a rotating shaft and a bearing assembly. The bearing assembly is configured to support the rotating shaft. The bearing assembly has a first bearing and a second bearing. The first bearing is configured to support an axial load of the rotating shaft when a forward thrust of the rotating shaft is greater than ten percent. The second bearing is configured to support the axial load of the rotating shaft when a thrust of the rotating shaft is between ten percent forward thrust and ten percent aft thrust, inclusive of the end points.

Abstract: A high-pressure (HP) rotor control system includes an HP rotor and a controller. The HP rotor includes a plurality of rotor blades that rotate about a centerline axis, and a plurality of variable stator vanes (VSVs) that are rotatable about a variable stator vane (VSV) pitch axis. The plurality of VSVs are disposed at an incidence angle. The controller controls the plurality of VSVs to rotate the plurality of VSVs about the VSV pitch axis to change the rotor incidence angle of the plurality of VSVs as the HP rotor approaches a thrust crossover condition.

Abstract: A gas turbine engine includes a compressor section having rotor shaft assembly and a stator shroud assembly including a stator shroud casing surrounding the compressor rotor shaft assembly, a compressor flow passage being defined between the compressor rotor shaft assembly and the stator shroud casing. A compressor bleed air system includes a compressor bleed air duct that includes a sloped inlet portion, such as a NACA submerged inlet portion, in the stator shroud casing. Alternatively, stator vanes at a compressor bleed air passage may have a NACA inlet scoop and an airflow passage through the stator vane providing a bleed airflow to a cavity, which has airflow passages providing bleed air to an upstream side of the bleed air passage.

Abstract: A gas turbine engine including a rotating shaft and a bearing assembly. The bearing assembly is configured to support the rotating shaft. The bearing assembly has a first bearing and a second bearing. The first bearing is configured to support an axial load of the rotating shaft when a forward thrust of the rotating shaft is greater than ten percent. The second bearing is configured to support the axial load of the rotating shaft when a thrust of the rotating shaft is between ten percent forward thrust and ten percent aft thrust, inclusive of the end points.

Abstract: Clearance control systems with thermal actuators are disclosed. An example thermally-actuated clearance control system for a gas turbine engine includes a compliant material; a high-conductive material coupled to a first surface of the compliant material, the high-conductive material thermally coupling the compliant material to a heated substance, the compliant material to expand radially-inward toward a fan blade when the high-conductive material provides heat; and an abradable material coupled to a second surface of the compliant material facing the fan blade.

Abstract: Methods, systems, and apparatus are disclosed to provide a pressurized fluid to components of a fluid pump. An example flow control system to provide a pressurized lubricant to a secondary flow network disposed within a fluid pump includes sensors to measure parameters of a fluid corresponding to fluid flow; a recirculation loop fluidly coupled to a secondary inlet of the pump, the recirculation loop to provide a first flowpath, wherein the secondary inlet is an inlet to the secondary flow network; a bypass circuit fluidly coupled to the secondary inlet to provide a second flowpath; and a controller to direct the fluid flow to the first flowpath or the second flowpath based on sensor data from the sensor, the sensor data indicative of a state of the fluid.

Abstract: A turbomachine including a turbine rotor, a compressor rotor, and a shaft, and at least one balance weight assembly connected to the shaft. The shaft drivingly connects the turbine rotor with the compressor rotor to rotate the compressor rotor about a rotational axis when the turbine rotor rotates about the rotational axis. The at least one balance weight assembly including a first chamber, at least one additional chamber, and a balance weight movable between the first chamber and the at least one additional chamber.

Abstract: Clearance control systems with thermal actuators are disclosed. An example thermally-actuated clearance control system for a gas turbine engine includes a compliant material; a high-conductive material coupled to a first surface of the compliant material, the high-conductive material thermally coupling the compliant material to a heated substance, the compliant material to expand radially-inward toward a fan blade when the high-conductive material provides heat; and an abradable material coupled to a second surface of the compliant material facing the fan blade.