An auxiliary power unit for an aircraft, having a compressor, an intercooler including first conduit(s) having an inlet in fluid communication with the compressor outlet and second conduit(s) configured for circulation of a coolant therethrough, an engine core having an inlet in fluid communication with an outlet of the first conduit(s), and a bleed conduit in fluid communication with the outlet of the first conduit(s) through a bleed air valve. The auxiliary power unit may include a generator in driving engagement with the shaft of the engine core to provide electrical power for the aircraft. A method of providing compressed air and electrical power to an aircraft is also discussed.

An energy storage system is disclosed. The energy storage system includes a turbo train drive, a hot heat sink, and a reservoir. The turbo train drive is in mechanical communication with a compressor and an expander. The hot heat sink is in thermal communication between an output of the compressor and an input of the expander. The reservoir is in thermal communication between an output of the expander and an input of the compressor. The compressor and the expander, via the turbo train drive, are operable between a charging function for charging the hot heat sink and a discharging function for discharging the hot heat sink.

A propulsion system includes a first compressor in fluid communication with a fluid source. A first conduit is coupled to the first compressor, and a heat exchanger is in fluid communication with the first compressor via the first conduit. A second conduit is positioned proximal to the heat exchanger. A combustor is in fluid communication with the heat exchanger via the second conduit and is configured to generate a high-temperature gas stream. A third conduit is coupled to the combustor, and a first thrust augmentation device is in fluid communication with the combustor via the third conduit. The heat exchanger is positioned within the gas stream generated by the combustor.

A liquid fuel system for an aircraft engine includes a first fuel supply conduit hydraulically connected to a fuel source, a second fuel supply conduit hydraulically connected to the engine, a fuel return conduit hydraulically connected to the second fuel supply conduit, and a fuel pump. The fuel pump has a main inlet hydraulically connected to the first fuel supply conduit, an outlet hydraulically connected to the second fuel supply conduit, and an intermediate inlet hydraulically connected to the fuel return conduit. The intermediate inlet is located between the main inlet and the outlet and in use has a pressure between the main inlet pressure and the outlet pressure. A method of supplying a liquid fuel to an aircraft engine is also described.

Systems and methods for reducing the pressure of a first pressurized fluid, thereby reducing the temperature of the pressurized fluid, and utilization of the reduced-pressure and temperature fluid to cool a second fluid. Such an approach can enable a reduction in the size and weight of a hydraulic system, utilize waste energy in a system, and/or minimize electrical power requirements of a system, among other benefits.

A gas turbine engine has a fan and a compressor section with a first lower pressure location and a second higher pressure location. A heat exchanger and a higher pressure tap from the second higher pressure location pass through the heat exchanger. Air in the higher pressure tap is cooled by air from a lower pressure tap from the first lower pressure location. A valve controls flow to the heat exchanger from the lower pressure tap, the valve being controlled to limit flow from the lower pressure tap under certain conditions.

A gas turbine engine has a compressor section with a low pressure compressor and a high pressure compressor having a downstream end. A cooling air system includes a tap from a location upstream of the downstream most location. The tap passes air to a boost compressor, and the boost compressor passes the air back to a location to be cooled. The boost compressor is driven by a shaft in the engine through an epicyclic gear system. A speed control changes the relative speed between an input and an output to the epicyclic gear system.

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.

A ventilation flow path, a cooling air flow path, a mixing space, and a mixed air flow path are formed in a gas turbine rotor. The ventilation flow path guides compressed air farther on an axially upstream side than an air discharge port of a compressor to an interior of a compressor rotor as compressor extracted air. The cooling air flow path guides cooling air to a part farther on an axially downstream side than the air discharge port. The compressor extracted air and the cooling air are mixed in the mixing space. The mixed air flow path guides mixed air containing the compressor extracted air and the cooling air into a turbine rotor.

A gas turbine engine includes a plurality of rotating components housed within a main compressor section and a turbine section. A first tap is connected to the main compressor section and configured to deliver air at a first pressure. A heat exchanger is connected downstream of the first tap. A cooling air valve is configured to selectively block flow of cooling air across the heat exchanger. A cooling compressor is connected downstream of the heat exchanger. A shut off valve stops flow between the heat exchanger and the cooling compressor. A second tap is configured to deliver air at a second pressure which is higher than the first pressure. A mixing chamber is connected downstream of the cooling compressor and the second tap. The mixing chamber is configured to deliver air to at least one of the plurality of rotating components. A system stops flow between the cooling compressor and the plurality of rotating components. A controller is configured to modulate flow between the heat exchanger and the plurality of rotating components under certain power conditions of the gas turbine engine. The controller is programmed to control the cooling air valve, the shut off valve and the system such that flow is stopped between the heat exchanger and the cooling compressor only after the cooling compressor has been stopped.