Abstract: A fuel system can include a first fuel circuit, a second fuel circuit, and an inert gas purge system operatively connected to both the first fuel circuit and the second fuel circuit to purge at least a portion of either or both of the first and/or second fuel circuit. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The first fuel circuit can include a first fuel manifold configured to fluidly communicate a first fuel supply with at least one dual fuel nozzles downstream of the first fuel manifold.

Abstract: A fuel system can include a first fuel circuit, a second fuel circuit, and an inert gas purge system operatively connected to both the first fuel circuit and the second fuel circuit to purge at least a portion of either or both of the first and/or second fuel circuit. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The first fuel circuit can include a first fuel manifold configured to fluidly communicate a first fuel supply with at least one dual fuel nozzles downstream of the first fuel manifold.

Abstract: A fuel supply system for an aircraft engine, comprises a gaseous fuel source and a fuel nozzle. The fuel nozzle includes a housing having a housing interior chamber and a fuel swirler disposed inside the housing interior chamber. The fuel swirler is fluidly connected to the gaseous fuel source for directing gaseous fuel to a combustor of the aircraft engine. The fuel swirler defines a gaseous fuel path extending from a fuel inlet to a fuel outlet. The gaseous fuel path includes a plurality of discrete apertures distributed around a circumference of the fuel swirler, each of the plurality of discrete apertures having a cross-sectional area selected to prevent a flame from propagating in an upstream direction through the gaseous fuel path towards the gaseous fuel source.

Abstract: A fuel supply system for an aircraft engine, comprises a gaseous fuel source and a fuel nozzle. The fuel nozzle includes a housing having a housing interior chamber and a fuel swirler disposed inside the housing interior chamber. The fuel swirler is fluidly connected to the gaseous fuel source for directing gaseous fuel to a combustor of the aircraft engine. The fuel swirler defines a gaseous fuel path extending from a fuel inlet to a fuel outlet. The gaseous fuel path includes a plurality of discrete apertures distributed around a circumference of the fuel swirler, each of the plurality of discrete apertures having a cross-sectional area selected to prevent a flame from propagating in an upstream direction through the gaseous fuel path towards the gaseous fuel source.

Abstract: A fuel system can include a first fuel circuit, a second fuel circuit, and an inert gas purge system operatively connected to both the first fuel circuit and the second fuel circuit to purge at least a portion of either or both of the first and/or second fuel circuit. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The first fuel circuit can include a first fuel manifold configured to fluidly communicate a first fuel supply with at least one dual fuel nozzles downstream of the first fuel manifold.