Methods and systems of operating a gas turbine engine in a low-power condition are provided. In one embodiment, the method includes supplying fuel to a combustor by supplying fuel to a first fuel manifolds and a second fuel manifold of the gas turbine engine. The method also includes, while supplying fuel to the combustor by supplying fuel to the first fuel manifold: stopping supplying fuel to the second fuel manifold; and using a pump to drive gas into the second fuel manifold to flush fuel in the second fuel manifold into the combustor and hinder coking in the second fuel manifold and associated fuel nozzles.

Methods and systems of operating a gas turbine engine in a low-power condition are provided. In one embodiment, the method includes supplying fuel to a combustor by supplying fuel to a first fuel manifold and a second fuel manifold of the gas turbine engine. The method also includes, while supplying fuel to the combustor by supplying fuel to the first fuel manifold: stopping supplying fuel to the second fuel manifold; and supplying pressurized air to the second fuel manifold to flush fuel in the second fuel manifold into the combustor and hinder coking in the second fuel manifold and associated fuel nozzles.

A gas turbine engine comprising a variable geometry combustor having pilot fuel injectors and main fuel injectors; a fuel metering system configured to control fuel flow to the pilot fuel injectors and the main fuel injectors; a variable geometry airflow arrangement for the variable geometry combustor, which is configured to vary the airflow through the pilot fuel injectors and/or the main fuel injectors; a control system configured to control the variable geometry airflow arrangement in dependence upon airflow delivered to the combustor, the fuel flow to the pilot fuel injectors and the main fuel injectors, and a target index of soot emissions, thereby controlling airflow through the pilot fuel injectors and/or the main fuel injectors and hence the quantity of soot produced by combustion.

A system includes a flow inlet conduit and a primary conduit that branches from the flow inlet conduit for delivering flow to a set of primary nozzles. An equalization bypass valve (EBV) connects between the flow inlet conduit and a secondary conduit for delivering flow to a set of secondary nozzles. The EBV is connected to an equalization conduit (EC) to apportion flow from the flow inlet conduit to the secondary conduit. A pressure equalization solenoid (PES) is connected to the EC to selectively connect at least one of a servo supply pressure (PFA) conduit or return pressure (PDF) conduit into fluid communication with the EC. A relief management valve (RMV) is connected in the PDF conduit.

A system includes a flow inlet conduit and a primary conduit that branches from the flow inlet conduit for delivering flow to a set of primary nozzles. An equalization bypass valve (EBV) connects between the flow inlet conduit and a secondary conduit for delivering flow to a set of secondary nozzles. The EBV is connected to an equalization conduit (EC) to apportion flow from the flow inlet conduit to the secondary conduit. A pressure equalization solenoid (PES) is connected to the EC to selectively connect at least one of a servo supply pressure (PFA) conduit or return pressure (PDF) conduit into fluid communication with the EC. A relief management valve (RMV) is connected in the PDF conduit.

A structure for damping at a fluid manifold assembly for an engine is generally provided. The fluid manifold assembly includes a first walled conduit defining a first fluid passage therewithin. A flow of fluid defining a first frequency is permitted through the first fluid passage. A second walled conduit includes a pair of first portions each coupled to the first walled conduit. A second portion is coupled to the pair of first portions. A second fluid passage is defined through the first portion and the second portion in fluid communication with the first fluid passage. The flow of fluid is permitted through the second fluid passage at a second frequency approximately 180 degrees out of phase from the first frequency.

Fuel distribution manifolds and combustors are provided. A fuel distribution manifold includes a main body and a fuel circuit that is defined within the main body. The fuel circuit includes an inlet section extending generally axially from an inlet to a first branch section and a second branch section. The first branch section and the second branch section diverge circumferentially away from each other as they extend axially from the inlet section to a respective first outlet and a respective second outlet.

Fuel distribution manifolds and combustors are provided. A fuel distribution manifold includes a main body and a fuel circuit that is defined within the main body. The fuel circuit includes an inlet section extending generally axially from an inlet to a first branch section and a second branch section. The first branch section and the second branch section diverge circumferentially away from each other as they extend axially from the inlet section to a respective first outlet and a respective second outlet.

A fuel pump system, comprising an inlet line and a motorized pump, a first selector valve in fluid communication with an inlet line at a first inlet port and in fluid communication with the motorized pump outlet via a first outlet branch at a second inlet port to receive fuel from the motorized pump outlet. The system can also include a main fuel pump in fluid communication with the first selector valve and a second selector valve, wherein the second selector valve can be in fluid communication with the main fuel pump and in fluid communication with the motorized pump outlet.

A fuel pump system, comprising an inlet line and a motorized pump, a first selector valve in fluid communication with an inlet line at a first inlet port and in fluid communication with the motorized pump outlet via a first outlet branch at a second inlet port to receive fuel from the motorized pump outlet. The system can also include a main fuel pump in fluid communication with the first selector valve and a second selector valve, wherein the second selector valve can be in fluid communication with the main fuel pump and in fluid communication with the motorized pump outlet.