A fuel metering system includes a pump with an inlet and an outlet, a first flow path including a first valve fluidically connected to the outlet of the pump, and a second flow path including a second valve fluidically connected to the outlet of the pump, a third valve, and a fourth valve. An electrohydraulic servo valve in a first position hydraulically connects the inlet of the pump to the first, third, and fourth valves to close the first valve, open the third valve, open a first window of the fourth valve, and close a second window of the fourth valve. The electrohydraulic servo valve in a second position hydraulically connects the outlet of the pump to the first, third, and fourth valves to open the first valve, close the third valve, close the first window of the fourth valve, and open the second window of the fourth valve.

A nozzle for a combustor in which a fuel containing hydrogen is burned is provided. The nozzle includes a first tube disposed in a center of the nozzle and having a first diameter, a plurality of second tubes circumferentially disposed around the first tube to be spaced apart from the first tube and each having a second diameter smaller than that of the first tube, and a plurality of third tubes disposed around the first tube and each having a diameter smaller than the second diameter, wherein the first tube, the plurality of second tubes, and the plurality of third tubes are arranged in parallel with each other.

A system mounted on a skid for use in fracturing operations is disclosed along with an associated method. The system includes a line heater on the skid to enable heating of fuel to be used with a turbine generator and includes one or more pressure regulators coupled to the line heater to enable adjustment of a pressure associated with the fuel.

A system mounted on a skid for use in fracturing operations is disclosed along with an associated method. The system includes a line heater on the skid to enable heating of fuel to be used with a turbine generator and includes one or more pressure regulators coupled to the line heater to enable adjustment of a pressure associated with the fuel.

There are describes methods and systems for operating an engine coupled to a fuel system having a fuel manifold configured to supply fuel to a combustor of the engine. The method comprises receiving a gaseous fuel flow request indicative of a change in demand for gaseous fuel to the engine; applying a fuel loss bias to the gaseous fuel flow request to obtain a biased fuel flow request, the fuel loss bias associated with a change in mass flow rate of the gaseous fuel from the fuel manifold to the combustor in response to the change in demand; and causing the gaseous fuel to flow into the combustor in accordance with the biased fuel flow request.

A method of identifying a fuel contained in a fuel tank of an aircraft and arranged to power a gas turbine engine of the aircraft is performed by processing circuitry of the aircraft and includes: obtaining at least one fuel characteristic of any fuel already present in the fuel tank prior to refuelling; determining at least one fuel characteristic of a fuel added to the fuel tank on refuelling; and calculating at least one fuel characteristic of the resultant fuel in the fuel tank after refuelling. The method may further controlling the propulsion system of the aircraft based on the calculated at least one fuel characteristic of the resultant fuel in the fuel tank after refuelling.

A method of identifying a fuel contained in a fuel tank of an aircraft and arranged to power a gas turbine engine of the aircraft is performed by processing circuitry of the aircraft and includes: obtaining at least one fuel characteristic of any fuel already present in the fuel tank prior to refuelling; determining at least one fuel characteristic of a fuel added to the fuel tank on refuelling; and calculating at least one fuel characteristic of the resultant fuel in the fuel tank after refuelling. The method may further controlling the propulsion system of the aircraft based on the calculated at least one fuel characteristic of the resultant fuel in the fuel tank after refuelling.

A method of determining one or more fuel characteristics of an aviation fuel for powering a gas turbine engine of an aircraft includes: measuring one or more trace substance parameters of the fuel, the one or more trace substance parameters each associated with a respective trace substance in the fuel; and determining one or more fuel characteristics of the fuel based on the one or more trace substance parameters. Further, a fuel characteristic determination system, a method of operating an aircraft, and an aircraft.

A gas turbine facility includes: a fuel pipe connected to a fuel supply facility; a fuel supply pipe connected to a combustor of a gas turbine; a fuel treating pipe connected to a fuel treating apparatus that treats a fuel; and a three-way valve having an inlet port connected to the fuel pipe, a first outlet port connected to the fuel supply pipe, and a second outlet port connected to the fuel treating pipe.

A fuel control system for an aircraft engine, comprises a fuel feed conduit including an inlet end and an outlet end. A fuel metering mechanism is disposed in the fuel feed conduit between the inlet end and the outlet end operable to regulate flow through the fuel feed conduit. A position feedback sensor is operatively connected to the fuel metering mechanism and operable to generate a signal indicative of a position of the fuel metering mechanism.