A bowed rotor prevention system for a gas turbine engine includes a bowed rotor prevention motor. A motor shaft of the bowed rotor prevention motor is operable to drive rotation of the gas turbine engine through an engine accessory gearbox. The motor shaft interfaces with an air turbine operable to rotate an output shaft mechanically linked to the engine accessory gearbox. The bowed rotor prevention system also includes a controller operable to engage the bowed rotor prevention motor and drive rotation of the gas turbine engine below an engine starting speed until a bowed rotor prevention threshold condition is met.

In one exemplary embodiment of the present disclosure a gas turbine engine defining a radial direction and an axial direction is provided. The gas turbine engine includes a stationary frame, a compressor and a turbine, the compressor or the turbine including a first plurality of rotor blades and a second plurality of rotor blades, the first plurality of rotor blades and second plurality of rotor blades alternatingly spaced along the axial direction and rotatable with one another; and a gearbox including a first gear coupled to the first plurality of rotor blades, a second gear coupled to the second plurality of rotor blades, and an intermediate gear positioned between the first gear and the second gear and coupled to the stationary frame, the intermediate gear defining an axis of rotation, the axis of rotation defining an angle with the radial direction less than about 75 degrees.

The present disclosure is directed to a gas turbine engine structure and method for reducing or mitigating bowed rotor. The method includes coupling a rotor assembly to a mechanical energy storage device via a clutch mechanism when the rotor assembly is at or below a speed limit below an idle speed condition; storing mechanical energy at the mechanical energy storage device via rotation of the rotor assembly at or below the speed limit; releasing mechanical energy from the mechanical energy storage device to rotate the rotor assembly following shutdown of the gas turbine engine; and rotating the rotor assembly via the mechanical energy from the mechanical energy storage device.

An auxiliary gearbox has a low speed input shaft driving a first plurality of accessories. A high speed input shaft drives a second plurality of accessories. The first plurality of accessories rotating about a first set of rotational axes, which are parallel to each other and perpendicular to a first plane. The second plurality of accessories rotating about a second set of rotational axes, which are parallel to each other and perpendicular to a second plane. The first and second planes extending in opposed directions away from a drive input axis of the high speed input shaft and the low speed input shaft. The low speed input shaft drives a variable speed transmission. A gas turbine engine is also disclosed.

A gas turbine engine has a low speed input shaft drives a first plurality of accessories. A high speed input shaft drives a second plurality of accessories. The first plurality of accessories rotating about a first set of rotational axes perpendicular to a first plane. The second plurality of accessories rotating about a second set rotational axes perpendicular to a second plane. The first and second planes extending in opposed directions away from a drive input axis. Compressed air is tapped and passes through a heat exchanger, then to a boost compressor, and then to at least one rotatable components in a main compressor section and a main turbine section. The boost compressor driven on a boost axis, which is non-parallel to the first set of rotational axes and the second set of rotational axes.

An accessory system for a gas turbine engine having a driveshaft with an axis of rotation is provided. The system includes a towershaft coupled to the driveshaft and rotatable about a towershaft axis of rotation. The towershaft includes a towershaft bevel gear. The system includes a primary shaft including a first bevel gear and a second bevel gear that each revolve about a primary shaft axis of rotation. The first bevel gear is coupled to the towershaft bevel gear. The system includes a secondary shaft including a third bevel gear and a fourth bevel gear that each revolve about a secondary shaft axis of rotation. The third bevel gear is coupled to the second bevel gear. The system includes a tertiary shaft including a fifth bevel gear that revolves about a tertiary shaft axis of rotation. The fifth bevel gear is coupled to the fourth bevel gear.

A power extraction and amplification system for a gas turbine engine is disclosed. In various embodiments, the power extraction and amplification system includes a low spool tower shaft configured for engagement with a low speed spool, a high spool tower shaft configured for engagement with a high speed spool, a first motor, a generator, a differential gear box operably coupled to the low spool tower shaft, to the first motor and to the generator, and a second motor operably coupled to the generator and the high spool tower shaft.

A drive architecture comprises a rotor and a gearbox for driving the rotor. A pair of input gears provides rotational drive to the gearbox. A first recuperative cycle engine drives one of the pair of gears and a second engine drives the other of the pair of gears. The first recuperative cycle engine and the second engine are both gas turbine engines. A power takeoff from a drive shaft of the second engine supplies rotational drive to drive at least one component in the first recuperative cycle drive.

A gas turbine includes a rotational body including a tie rod, a plurality of rotor disks arranged in an axial direction of the tie rod, and a plurality of blades radially arranged on an outer periphery of each rotor disk; a stationary body surrounding the rotational body and defining a working fluid flow space between opposing surfaces of the rotational and stationary bodies, the stationary body including a casing accommodating the rotational body and a plurality of vanes and diaphragms arranged on an inner surface of the casing, the vanes arranged alternately with the blades; and a compressor cleaner disposed at a plurality of compressor positions in the stationary body to spray a cleaning fluid into the working fluid flow space. The compressor positions are separated from each other in the axial direction, and the cleaning fluid is spayed at low pressure to enhance cleaning efficiency while protecting compressor components.

A disclosed turbofan engine includes a first spool including a first turbine; a second spool including a second turbine disposed axially forward of the first turbine, a first tower shaft engaged to the first spool, a second tower shaft engaged to the second spool, and a superposition gearbox including a sun gear, a plurality of intermediate gears engaged to the sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears. The second tower shaft is engaged to drive the sun gear. A starter is selectively coupled to the sun gear through a starter clutch. A first clutch selectively couples the first tower shaft to the ring gear and a second clutch selectively couples the ring gear to a static structure of the engine. An accessory gearbox is driven by an output of the superposition gearbox.