A fuel system can include a selection and shutoff valve (SSOV) configured to allow a primary flow having a primary flow pressure to pass therethrough in a first state such that the primary flow can travel to an output line. The SSOV can also be configured to shut off the primary flow in a second state to prevent the primary flow from travelling to the output line. In the second state, the SSOV can be configured to allow a secondary flow from a secondary flow source to pass therethrough such that the secondary flow can travel to the output line.

In accordance with at least one aspect of this disclosure, a system for active flow control includes one or more flow control devices configured to control flow between a fluid source and a fluid destination, and a control module configured to control a flow area of each of the one or more flow control devices with fluid provided from the fluid source flowing to the fluid destination through the one or more flow control devices.

A variable displacement pump can include a rotor having a plurality of vanes, a cam ring surrounding the rotor and vanes, the vanes configured to extend from the rotor and contact an inner cam surface of the cam ring, and a retainer configured to contact the cam ring and to move the cam ring relative to the rotor to modify a pumping action. The pump can also include a direct actuation mechanism configured to control a position of the retainer to control a position of the cam ring and the pumping action.

A variable displacement pump can include a rotor having a plurality of vanes, a cam ring surrounding the rotor and vanes, the vanes configured to extend from the rotor and contact an inner cam surface of the cam ring, and a retainer configured to contact the cam ring and to move the cam ring relative to the rotor to modify a pumping action. The pump can also include a direct actuation mechanism configured to control a position of the retainer to control a position of the cam ring and the pumping action.

An aircraft having an engine and a throttle thereof. The throttle has a throttle body (1), the throttle body (1) is provided with a cavity (10) and comprises an inlet port (11) and an outlet port (12) both of which are connected to the cavity (10); a plurality of fuel injectors (2), each of the fuel injectors (2) is arranged on the throttle body (1) and can spray fuel into the cavity (10) of the throttle body (1); and an air filter (3). The air filter (3) is arranged on the throttle body (1) and connected to the inlet port (11). There is an air door (4) that can rotate in the cavity (10) to connect or block the inlet port (11) and the outlet port (12). Additionally, there is an air door driving part connected to the air door (4) and controls the rotation of the air door (4).

A fuel supply system for a turbomachine, comprising a fuel circuit comprising pressurizer at the output of the circuit, a pump arranged to send into the circuit a fuel flow rate which is an increasing function of the rotational speed of a shaft of the pump, and a control circuit arranged to control the device to comply with a flow rate setpoint at the output of the fuel circuit. The system further comprises a feedforward corrector circuit configured to calculate an increment of the flow rate setpoint as a function of the engine speed of the turbomachine and of a variation in the engine speed of the turbomachine, and to add this increment to the flow rate setpoint. A method of regulating the pump is also described.

A fuel supply system for a turbomachine, comprising a fuel circuit comprising pressurizer at the output of the circuit, a pump arranged to send into the circuit a fuel flow rate which is an increasing function of the rotational speed of a shaft of the pump, and a control circuit arranged to control the device to comply with a flow rate setpoint at the output of the fuel circuit. The system further comprises a feedforward corrector circuit configured to calculate an increment of the flow rate setpoint as a function of the engine speed of the turbomachine and of a variation in the engine speed of the turbomachine, and to add this increment to the flow rate setpoint. A method of regulating the pump is also described.

A system includes an air cooling system having a heat exchanger, a fan, and a mount. The heat exchanger includes an inlet, an outlet, and a heat exchange conduit between the inlet and the outlet. The inlet is configured to couple to a bleed system of a gas turbine system to extract a bleed flow. The heat exchanger is configured to cool the bleed flow along the heat exchange conduit in a surrounding air to produce a cooled bleed flow. The outlet is configured to couple to a fuel purge system of the gas turbine system to supply the cooled bleed flow as a fuel purge flow. The fan is configured to force an airflow from the surrounding air through the heat exchanger. The mount is configured to mount the air cooling system outside of an enclosure surrounding the gas turbine system.

A system includes an air cooling system having a heat exchanger, a fan, and a mount. The heat exchanger includes an inlet, an outlet, and a heat exchange conduit between the inlet and the outlet. The inlet is configured to couple to a bleed system of a gas turbine system to extract a bleed flow. The heat exchanger is configured to cool the bleed flow along the heat exchange conduit in a surrounding air to produce a cooled bleed flow. The outlet is configured to couple to a fuel purge system of the gas turbine system to supply the cooled bleed flow as a fuel purge flow. The fan is configured to force an airflow from the surrounding air through the heat exchanger. The mount is configured to mount the air cooling system outside of an enclosure surrounding the gas turbine system.

Methods and systems for operating an engine coupled to a fuel system having at least one fuel manifold configured to supply fuel to a combustor of the engine are described. The method comprises, when the engine is active, supplying fuel to the combustor by supplying gaseous fuel from a gaseous fuel supply to the at least one fuel manifold, and when the engine is inactive, purging the at least one fuel manifold by supplying inert gas from an inert gas supply to the at least one fuel manifold.