Abstract: A fuel heating system for a gas turbine engine comprises a first heat exchanger, a second heat exchanger, a fuel pump and a valve. The first heat exchanger produces a heated air flow. The second heat exchanger receives the heated air flow from the first heat exchanger. The fuel pump provides a fuel flow. The valve is coupled to the fuel pump to intermittently include the second heat exchanger in the fuel flow based on a temperature of the fuel flow. A method of heating fuel in a gas turbine engine comprises providing fuel to a gas turbine engine with a fuel pump to sustain a combustion process, heating a flow of air with exhaust gas from the combustion process, and heating fuel from the fuel pump en route to the gas turbine engine with the flow of air based on a temperature of the fuel.

Abstract: A gas turbine engine according to one disclosed non-limiting embodiment of the present disclosure includes an engine case, a multiple of fuel injectors mounted to the engine case, and a fire shield mounted to the engine case to surround at least one, but less than all, of the multiple of fuel injectors. In a further embodiment of the foregoing embodiment, the fire shield includes a sheet metal alloy layer. In the alternative or additionally thereto, in the foregoing embodiment the fire shield includes a composite cloth on an interior of the sheet metal alloy layer with respect to the engine case.

Abstract: A fuel heating system for a gas turbine engine comprises a first heat exchanger, a second heat exchanger, a fuel pump and a valve. The first heat exchanger produces a heated air flow. The second heat exchanger receives the heated air flow from the first heat exchanger. The fuel pump provides a fuel flow. The valve is coupled to the fuel pump to intermittently include the second heat exchanger in the fuel flow based on a temperature of the fuel flow. A method of heating fuel in a gas turbine engine comprises providing fuel to a gas turbine engine with a fuel pump to sustain a combustion process, heating a flow of air with exhaust gas from the combustion process, and heating fuel from the fuel pump en route to the gas turbine engine with the flow of air based on a temperature of the fuel.

Abstract: An auxiliary power unit includes a turbomachine coupled to a generator. A flow path is arranged through the generator and is configured to provide fluid to the generator. A deprime valve is arranged in the flow path and is configured to pulse fluid flow to the generator in response to a command. A controller is configured to send the command to the deprime valve to pulse the fluid flow throughout operation of the auxiliary power unit.

Abstract: An exemplary lubrication system includes a flow path that carries fluid from a fluid supply through at least a portion of an auxiliary power unit to an outlet separate from the fluid supply. The fluid supply is pressurized to move the fluid along the flow path.