A system can include a gas turbine and a processing system. The gas turbine can include a compressor coupled to a turbine through a shaft. The processing system can be configured to: automatically transition an operating condition of the system through a plurality of operating states; determine an efficiency of the system at each of a plurality of the operating states; for each of the plurality of operating states: select a future operating state of the system based on the determined efficiency of the current operating state.

In accordance with at least one aspect of this disclosure, there is provided a fuel control system for gaseous fuel in an aircraft. The system includes a control module operatively connected to a metering device in a fuel flow conduit, the control module operable to control the flow of fuel through the fuel flow conduit. The control module includes an input line operable to receive a command input indicative of a requested engine state. In embodiments, the control module includes a compressibility logic and machine readable instructions. The machine readable instruction can be configured to cause the control module to control the metering device to achieve the requested engine state based on a compressibility factor input from the compressibility logic.

A hybrid electric propulsion system includes a gas turbine engine having at least one compressor section and at least one turbine section operably coupled to a shaft. The hybrid electric propulsion system includes an electric motor configured to augment rotational power of the shaft of the gas turbine engine. A controller is operable to determine an estimate of hybrid electric propulsion system parameters based on a composite system model and sensor data, determine a model predictive control state and a prediction based on the hybrid electric propulsion system parameters and the composite system model, determine a model predictive control optimization for a plurality of hybrid electric system control effectors based on the model predictive control state and the prediction using a plurality of reduced-order partitions of the composite system model, and actuate the hybrid electric system control effectors based on the model predictive control optimization.

A thermal energy system for use with an aircraft includes a cooling loop and a cooler. The cooling loop includes a fluid conduit and a pump configured to move fluid through the fluid conduit to transfer heat from a heat source to the fluid in the fluid conduit to cool the heat source. The cooler includes an air-stream heat exchanger located in a duct and is in thermal communication with the fluid conduit to transfer heat between the fluid in the cooling loop and the air passing through the duct.

A system for operating a gas turbine engine to mitigate the risk of ice formation within the engine, the system including a controller arranged to control at least one operational parameter of the engine such that the engine operates in a safe zone; and, a processor configured to function as a determining module to make a comparison between values and determine whether the engine is operating within a safe zone based on at least a core pressure parameter relating to the pressure within the engine and a core temperature parameter relating to the temperature within the engine, wherein the safe zone is defined by the product (multiplied) of the core pressure parameter and core temperature parameter being above a safe threshold.

A communication adapter of a gas turbine engine of an aircraft includes a communication interface configured to wirelessly communicate with an offboard system and to communicate with an engine control of the gas turbine engine. The communication adapter also includes a memory system and processing circuitry configured to receive one or more configuration items from the offboard system, confirm an authentication between the communication adapter and the engine control, apply a cryptographic algorithm using one or more parameters received and cryptographic information to decrypt the one or more configuration items, wherein the cryptographic information includes a combination of received cryptographic information and previously stored cryptographic information, and transfer the one or more configuration items to the engine control based on the authentication.

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.

There is provided a system and a method for controlling a tip clearance between a turbine casing and turbine blade tips of an aircraft engine. At least one operational parameter of the aircraft engine is obtained. Based on the at least one operational parameter, a current value of the tip clearance and a target value of the tip clearance are determined. A limiting factor to be applied to the target value of the tip clearance is computed. The limiting factor is applied to the target value of the tip clearance to obtain a tip clearance demand for the aircraft engine. A tip clearance control apparatus of the aircraft engine is controlled based on a difference between the current value of the tip clearance and the tip clearance demand.

A sleeve valve includes an inlet port and an outlet port. A sleeve is movable to close flow from the inlet port to the outlet port. The sleeve valve has a sleeve biased to an open position at which it allows flow from the inlet port to the outlet port by a spring. Pressure in a pressure chamber urges the sleeve to a closed position at which it blocks flow from the inlet port to the outlet port. A line pressure conduit communicates the fluid chamber into the pressure chamber. Pressurized air is supplied to the pressure chamber through a selectively closed valve. The selectively closed valve is opened to allow the flow of high pressure air from a pressure source into the pressure chamber to move the sleeve to a closed position. A bleed air system for a gas turbine engine is also disclosed.

A system (1) for vibration management comprises a stator (24, 45); a rotor (26) being mounted rotatably with respect to the stator (24, 45) about a rotational axis (9); one or more active devices (41A-41C) adapted to apply forces and/or moments on the rotor (26) and/or on the stator (24, 45); at least two sensors (42) for measuring vibrational parameter values with respect to two or more different positions, particularly along the rotational axis (9); and a controller (44) adapted to provide control signals to the one or more active devices (41A-41C) based on the vibrational parameter values of the at least two sensors (42) and on the respective position.