A passive flow splitting system for use in a turbine engine control system to provide split fuel flow to two fuel manifolds to supply primary and secondary fuel injectors for the particular combustion zones thereof utilizing intentionally different split ratios dependent on ascending or descending combustion fuel flow is provided. The system includes a passive fuel divider valve (FDV) that includes a primary piston and a secondary piston. The primary piston is moveable independently from the secondary piston during a portion of its stroke, and is hydro-locked to the secondary piston during another portion of its stroke. An ecology valve is also provided to purge the fuel from the primary and/or secondary manifolds during different modes of operation. A transfer valve is included to control the position of ecology piston of the ecology valve.

An aircraft includes an engine, a fuel tank, a chamber, a system, and an introduction line. The chamber is located in the tank, occupies only a part of the tank, and includes a sensor for measuring a property of the fuel. The system injects fuel into the line. The introduction line introduces fuel from the injection system into the chamber. The introduction line includes a valve capable of preventing an introduction of fuel from the injection system into the chamber via the line.

A micromixer injector includes a fuel plenum to receive a supply of fuel. A plurality of premixing tubes extend through the fuel plenum. Each tube has a plurality of fuel holes formed therein to receive the supply of fuel for mixing with air in the tube. The micromixer has a tapering profile such that an overall inlet area of the plurality of premixing tubes on an upstream face of the micromixer is larger than an overall outlet area of the plurality of premixing tubes on a downstream face such that the plurality of premixing tubes are relatively spaced-apart at the upstream face and more densely packed at the downstream face. Additionally, an air inlet of each tube has a first geometrical shape and the outlet of each tube has a second geometrical shape that is different from the first geometrical shape.

A rich-quench-lean combustor assembly for a gas turbine engine includes a liner extending between a forward end and an aft end. The liner includes a plurality of quench air jets positioned between the forward end and the aft end. The combustor assembly additionally includes a dome attached to or formed integrally with the liner, the dome and the liner together defining at least in part a combustion chamber. A fuel nozzle is attached to the dome, the fuel nozzle configured as a premix fuel nozzle for providing a substantially homogenous mixture of fuel and air to the combustion chamber, the mixture of fuel and air having an equivalence ratio of at least 1.5.

A gas turbine engine shut-down system includes a pump configured to draw a flow of fuel from a source, a fuel nozzle configured to receive the flow of fuel from the pump, a fuel shut-off valve in fluid communication with the pump, a recirculation circuit for circulating excess fuel to a location upstream of the pump; a solenoid valve in communication with the pump and the recirculation circuit; and a fuel-bypass valve. The fuel-bypass valve includes a first opening connected to the fuel pump, a second opening connected to the fuel shut-off valve, a third opening connected to the recirculation circuit, a fourth opening connected to the solenoid valve, and a piston disposed within the fuel-bypass valve and movable between a plurality of positions.

A premix pilot nozzle is disclosed herein. The premix pilot nozzle includes a nozzle body. The nozzle body includes a forward wall, an aft wall, an outer band that extends between the forward wall and the aft wall and a tip portion that extends axially downstream from the aft wall. The nozzle body further defines a fuel inlet plenum that extends coaxially within the nozzle body, a fuel distribution plenum that is defined within the nozzle body radially outwardly from and in fluid communication with the fuel inlet plenum, a plurality of premix passages that extend helically around the fuel inlet plenum within the fuel distribution plenum and a plurality of air passages annularly arranged around the plurality of premix passages. One or more premix passages of the plurality of premix passages are in fluid communication with the fuel distribution plenum.

Fuel injectors for gas turbine engines are provided herein. The fuel injectors include a nozzle configured to dispense fuel into a combustor of a gas turbine engine, a fuel conduit fluidly connecting a fuel source to the nozzle, and a heat pipe having a vaporization section and a condensation section, wherein the vaporization section is in thermal communication with the nozzle and the condensation section is in thermal communication with a cooling source of the gas turbine engine.

A premix pilot nozzle and fuel nozzle assembly are disclosed herein. The premix pilot nozzle includes a nozzle body having a forward wall axially spaced from an aft wall and an outer band that extends axially between the forward wall and the aft wall. An air tube extends coaxially within the nozzle body and defines a cooling air plenum within the nozzle body. A fuel tube extends coaxially within the nozzle body and circumferentially surrounds the air tube so as to define a fuel inlet plenum therebetween. A fuel distribution plenum is defined within the nozzle body and is in fluid communication with the fuel inlet plenum. The nozzle body further includes a plurality of premix tubes. Each premix tube extends helically around the fuel tube within the fuel distribution plenum. One or more of the premix tubes is in fluid communication with the fuel distribution plenum.

A method of accessing a nozzle tip assembly of a gas turbine engine fuel nozzle is disclosed. The fuel nozzle has a stem and a heat shield enclosing at least part of the stem. The nozzle tip assembly is disposed within an inner cavity of the stem. The method includes forming an opening in at least the heat shield of the fuel nozzle, the opening providing access to the inner cavity of the stem via a first end thereof. The first end of the cavity is positioned opposite to a fuel nozzle exit from which fuel is conveyed from the fuel nozzle. The method includes accessing the nozzle tip assembly in the inner cavity via the opening. The method includes closing the opening after accessing the nozzle tip assembly.

A gas turbine fuel heating system is disclosed having at least one coalescing filter configured to accept a main fuel supply and a plurality of fuel circuit heaters. Each fuel circuit heater can be configured to accept an independent fuel circuit portion of the main fuel supply leaving the at least one coalescing filter and also configured to accept a heating medium circuit portion of a heating medium. The system can have a plurality of scrubbers, a plurality of fuel circuit manifolds, and a plurality of fuel premix tubes. A controller circuit determines the MWI for each independent fuel circuit portion and adjusts the heating medium circuit portion passed to the corresponding fuel circuit heater to maintain at least one parameter selected from the group consisting of a baseline independent fuel circuit portion MWI setpoint and a predetermined independent fuel circuit portion nozzle gas injector pressure ratio.