In a fuel control system (10) for a gas turbine engine (1) having a gas generator (4) and a turbine (6) driven by the gas generator (4): a main fuel regulator (12) determines a demand (W.sub.fdem) of fuel flow (W.sub.f) to be introduced in the gas turbine engine (1), based on an input request (PLA); and a first limiter stage (14), operatively coupled to the main fuel regulator (12), causes an adjustment of the fuel flow (W.sub.f) based on engine safety operating limits. The first limiter stage (14) is provided with a Ngdot limiter (20) to cause an adjustment of the fuel flow (W.sub.f) when the gas generator speed rate of change (N.sub.gdot) is determined to overcome acceleration/deceleration scheduled safety limits; the Ngdot limiter (20) implements a predictor (23), to perform a prediction (W.sub.fdot) of the fuel flow rate of change (W.sub.fdot), or fuel flow (W.sub.f), allowing the gas generator speed rate of change (N.sub.gdot) to track a scheduled reference value (Ngdot.sub.ref).

A propulsion assembly for aircraft includes a single-shaft engine turbomachine including a combustion chamber and a rotatably mounted shaft that turns at a turbomachine rating; an electrical generator coupled to the shaft; and a control system. The control system includes a fuel pump that brings fuel into the combustion chamber at a fuel flow rate which is a direct function of an ambient pressure and of the turbomachine rating, and power electronics that are coupled to the electrical generator and that control an electrical power drawn off the electrical generator so as to attain a target turbomachine rating.

What is provided is a fuel supply system that includes a fuel gear pump that is driven by an electric motor and sends fuel in a fuel tank to a fuel nozzle that supplies fuel to the combustor, a controller that controls a rotational speed of the electric motor, and the flow rate measurer that measures the flow rate of fuel discharged from the fuel gear pump. When the difference between the fuel flow rate actually discharged from the electric motor and a target value of the flow rate is equal to or greater than a first threshold value with respect to the target value, the controller adjusts the rotational speed of the electric motor so that the measured value of the flow rate of the fuel discharged from the fuel gear pump approaches the target value.

A fuel power transfer system for an engine may include a cryogenic fuel supply, a fuel pump in fluid communication with the cryogenic fuel supply, a multi-position valve in fluid communication with the fuel pump and a combustion chamber of the engine, a fuel turbine operatively coupled to the fuel pump and having a primary discharge port in fluid communication with the combustion chamber, a primary heat exchanger in fluid communication between the multi-position valve and the fuel turbine, and a gearbox operatively coupled to the fuel turbine and the fuel pump and configured to transfer power from the fuel turbine to the engine.

A fuel power transfer system for an engine may include a cryogenic fuel supply, a fuel pump in fluid communication with the cryogenic fuel supply, a multi-position valve in fluid communication with the fuel pump and a combustion chamber of the engine, a fuel turbine operatively coupled to the fuel pump and having a primary discharge port in fluid communication with the combustion chamber, a primary heat exchanger in fluid communication between the multi-position valve and the fuel turbine, and a gearbox operatively coupled to the fuel turbine and the fuel pump and configured to transfer power from the fuel turbine to the engine.

In a fuel control system (10) for a gas turbine engine (1) having a gas generator (4) and a turbine (6) driven by the gas generator (4): a main fuel regulator (12) determines a demand (W.sub.fdem) of fuel flow (W.sub.f) to be introduced in the gas turbine engine (1), based on an input request (PLA); and a first limiter stage (14), operatively coupled to the main fuel regulator (12), causes an adjustment of the fuel flow (W.sub.f) based on engine safety operating limits. The first limiter stage (14) is provided with a Ngdot limiter (20) to cause an adjustment of the fuel flow (W.sub.f) when the gas generator speed rate of change (N.sub.gdot) is determined to overcome acceleration/deceleration scheduled safety limits; the Ngdot limiter (20) implements a predictor (23), to perform a prediction (W.sub.fdot) of the fuel flow rate of change (W.sub.fdot), or fuel flow (W.sub.f), allowing the gas generator speed rate of change (N.sub.gdot) to track a scheduled reference value (Ngdot.sub.ref).

In a fuel control system (10) for a gas turbine engine (1) having a gas generator (4) and a turbine (6) driven by the gas generator (4): a main fuel regulator (12) determines a demand (W.sub.fdem) of fuel flow (W.sub.f) to be introduced in the gas turbine engine (1), based on an input request (PLA); and a first limiter stage (14), operatively coupled to the main fuel regulator (12), causes an adjustment of the fuel flow (W.sub.f) based on engine safety operating limits. The first limiter stage (14) is provided with a Ngdot limiter (20) to cause an adjustment of the fuel flow (W.sub.f) when the gas generator speed rate of change (N.sub.gdot) is determined to overcome acceleration/deceleration scheduled safety limits; the Ngdot limiter (20) implements a predictor (23), to perform a prediction (W.sub.fdot) of the fuel flow rate of change (W.sub.fdot), or fuel flow (W.sub.f), allowing the gas generator speed rate of change (N.sub.gdot) to track a scheduled reference value (Ngdot.sub.ref).

A method of controlling a delivery pressure of an aircraft engine fuel system includes operating a rotodynamic fuel pump hydraulically connected to the fuel system to pump a fluid from an inlet of the rotodynamic pump and out of an outlet of the rotodynamic pump for delivery to the fuel system. The method further includes varying an angular relationship between the inlet and the outlet of the pump to control the delivery pressure. An aircraft engine fuel system and a rotodynamic pump are also described.

A method for reducing an engine core speed is disclosed, which includes determining a condition of an engine during operation of the engine, and controlling an engine turbine clearance based on the condition of the engine so as to influence the engine core speed. An engine system comprising an engine core speed reducing system is also disclosed.

A method for reducing an engine core speed is disclosed, which includes determining a condition of an engine during operation of the engine, and controlling an engine turbine clearance based on the condition of the engine so as to influence the engine core speed. An engine system comprising an engine core speed reducing system is also disclosed.