A fuel oxygen reduction unit for an engine is provided. The fuel oxygen reduction unit includes a contactor including a fuel inlet that receives an inlet fuel flow and a stripping gas inlet that receives an inlet stripping gas flow, the contactor configured to form a fuel/gas mixture; a separator that receives the fuel/gas mixture, the fuel oxygen reduction unit defining a circulation gas flowpath from the separator to the contactor; and a level control device that controls a level of the fuel/gas mixture inside the separator by regulating the inlet fuel flow to the contactor.

A turbine fracturing system and a controlling method thereof, a controlling apparatus and a storage medium are provided. The turbine fracturing system includes: N turbine fracturing apparatuses, wherein each of the N turbine fracturing apparatuses comprises a turbine engine, and N is an integer greater than or equal to 2; a fuel gas supply apparatus connected to the N turbine engines, wherein the fuel gas supply apparatus is configured to supply fuel gas and distribute the fuel gas to the N turbine engines as gaseous fuel; and a fuel liquid supply apparatus connected to at least one of the N turbine engines and configured to supply liquid fuel to at least one of the N turbine engines in a case that at least one of a flow rate and a pressure of the fuel gas decreases.

A fuel system for a gas turbine engine includes a main fuel pump generating a main fuel flow into a main fuel passage and a secondary pump generating a secondary fuel flow into a secondary flow passage. A first control valve is disposed in a passage between the main fuel passage and the secondary flow passage. The first control valve selectively directs an excess portion of the main fuel flow to the secondary flow passage to provide at least a portion of the secondary fuel flow.

A fuel system for a gas turbine engine includes a main fuel pump generating a main fuel flow into a main fuel passage and a secondary pump generating a secondary fuel flow into a secondary flow passage. A first control valve is disposed in a passage between the main fuel passage and the secondary flow passage. The first control valve selectively directs an excess portion of the main fuel flow to the secondary flow passage to provide at least a portion of the secondary fuel flow.

A heat exchange system for an aircraft engine includes a heat exchanger, a main conduit directing fuel to a combustion chamber of the aircraft engine, and a pump connected to the main conduit. A return conduit receives excess fuel outputted by the pump and exceeding a fuel requirement of the combustion chamber. The return conduit, which is connected to a fuel conduit of the heat exchanger, has an inlet connected to the main conduit downstream of the pump and an outlet connected to the main conduit upstream of the pump. An actuator has an inlet connected to the main conduit downstream of the pump and an outlet connected to the main conduit upstream of the pump while bypassing the heat exchanger, wherein a pressure differential between the actuator inlet and the actuator outlet remains substantially unchanged with variations of a fuel flow through the heat exchanger.

A heat exchange system for an aircraft engine includes a heat exchanger, a main conduit directing fuel to a combustion chamber of the aircraft engine, and a pump connected to the main conduit. A return conduit receives excess fuel outputted by the pump and exceeding a fuel requirement of the combustion chamber. The return conduit, which is connected to a fuel conduit of the heat exchanger, has an inlet connected to the main conduit downstream of the pump and an outlet connected to the main conduit upstream of the pump. An actuator has an inlet connected to the main conduit downstream of the pump and an outlet connected to the main conduit upstream of the pump while bypassing the heat exchanger, wherein a pressure differential between the actuator inlet and the actuator outlet remains substantially unchanged with variations of a fuel flow through the heat exchanger.

In one aspect of the present disclosure, there is provided a gas turbine engine. The gas turbine engine includes a primary gas path having, in fluid series communication: an air inlet, a compressor fluidly connected to the air inlet, a combustor fluidly connected to an outlet of the compressor, and a turbine section fluidly connected to an outlet of the combustor section. In embodiments, a hydrogen expansion turbine is in fluid communication to receive hydrogen from the gaseous hydrogen outlet of the heat exchanger. In certain embodiments, the gas turbine engine includes a heat exchanger having a gas conduit fluidly connected to the primary gas path, and a fluid conduit in fluid isolation from the gas conduit and in thermal communication with the gas conduit.

A metering valve has a main inlet port and a spool movable, and a housing outlet port in a housing. The spool has a metering inlet orifice selectively aligned with the main inlet port, and a metering outlet orifice selectively aligned with the main outlet port. The main inlet port communicates with the metering inlet orifice, and the outlet port communicates with the metering outlet orifice to each provide a metering orifice. The main outlet port communicates downstream to a minimum pressure valve. The minimum pressure valve has a piston biased to a closed position by a spring force, and a line downstream of the main outlet port acting against a face of the piston in opposition to the spring force to ensure a minimum pressure moving downstream past the piston to a use. A fuel system is also disclosed.

A metering valve has a shutoff position at which it blocks flow from the metering valve outlet line from reaching an outlet to a use. A spool has a first end and a second end. The housing has a first shoulder associated with the first end and a second shoulder associated with the second end. In the shutoff position, the spool has the first end spaced from the first shoulder, and the second end spaced from the second shoulder. A fuel system for a gas turbine engine is also disclosed.

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.