Abstract: Methods of managing fuel temperatures in fuel injectors for gas turbine engines include cooling fuel circuits by initiating fuel flow therethrough using opened, closed, and semi-open control techniques. A fuel injector for a gas turbine engine includes a feed arm having a fuel inlet fitting for delivering fuel to at least one fuel conduit extending through the feed arm. A nozzle body depends from the feed arm and has at least one fuel circuit extending therethrough. The fuel circuit is configured and adapted to receive fuel from the feed arm and to issue fuel from an exit orifice of the nozzle body. Sensing means are provided adjacent to the at least one fuel circuit. The sensing means are configured and adapted to provide temperature feedback in order to control fuel flow in the at least one fuel circuit to maintain fuel temperature within a predetermined range.

Abstract: An injector includes a main nozzle body defining a central axis and having a main fuel circuit. A pilot nozzle body is mounted inboard of the main nozzle body. The pilot nozzle body includes a pilot air circuit on the central axis with fuel circuitry radially outboard of the pilot air circuit for delivering fuel to a fuel outlet in a downstream portion of the pilot nozzle body. The fuel circuitry includes a primary pilot fuel circuit configured and adapted to deliver fuel to the fuel outlet and a secondary pilot fuel circuit configured and adapted to deliver fuel to the same fuel outlet.

Abstract: A fuel injector for a gas turbine engine includes a nozzle body defining a central axis and having a main fuel circuit. An air circuit is formed within the nozzle body inboard of the main fuel circuit. A primary pilot fuel circuit is formed within the nozzle body inboard of the air circuit. A secondary pilot fuel circuit is formed within the nozzle body inboard of the air circuit and outboard of the primary pilot fuel circuit.

Abstract: A lean direct injection fuel nozzle for a gas turbine is disclosed which includes a radially outer main fuel delivery system including a main inner air swirler defined in part by a main inner air passage having a radially inner wall with a diverging downstream surface, an intermediate air swirler radially inward of the main inner air swirler for providing a cooling air flow along the downstream surface of the radially inner wall of the main inner air passage, and a radially inner pilot fuel delivery system radially inward of the intermediate air swirler.

Abstract: A lean direct injection fuel nozzle for a gas turbine is disclosed which includes a radially outer main fuel delivery system including a main inner air swirler defined in part by a main inner air passage having a radially inner wall with a diverging downstream surface, an intermediate air swirler radially inward of the main inner air swirler for providing a cooling air flow along the downstream surface of the radially inner wall of the main inner air passage, and a radially inner pilot fuel delivery system radially inward of the intermediate air swirler.

Abstract: Methods of managing fuel temperatures in fuel injectors for gas turbine engines include cooling fuel circuits by initiating fuel flow therethrough using opened, closed, and semi-open control techniques. A fuel injector for a gas turbine engine includes a feed arm having a fuel inlet fitting for delivering fuel to at least one fuel conduit extending through the feed arm. A nozzle body depends from the feed arm and has at least one fuel circuit extending therethrough. The fuel circuit is configured and adapted to receive fuel from the feed arm and to issue fuel from an exit orifice of the nozzle body. Sensing means are provided adjacent to the at least one fuel circuit. The sensing means are configured and adapted to provide temperature feedback in order to control fuel flow in the at least one fuel circuit to maintain fuel temperature within a predetermined range.

Abstract: A multi-stage check valve includes a valve housing defining an internal valve chamber. A main valve member within the valve chamber of the valve housing has an internal valve chamber. In the first position thereof the main valve member blocks fuel below a predetermined main pressure from flowing through a main fuel path. In the second position thereof the main valve member is displaced to allow fuel above the predetermined main pressure to flow through the main fuel path. The multi-stage check valve also includes a pilot valve member within the valve chamber of the main valve member. In the first position thereof, the pilot valve member blocks fuel below a predetermined pilot pressure from flowing through a pilot fuel path. In the second position thereof, the pilot valve member is displaced to allow fuel above the predetermined pilot pressure to flow through the pilot fuel path.

Abstract: Valve systems for controlling a flow of fuel in a gas turbine engine and related methods are provided. In one embodiment, the valve system includes a supply conduit, a proportional valve portion, and a pulsating valve portion. The supply conduit is adapted and configured for receiving and carrying a flow of fuel. The proportional valve portion is in fluid connection with the supply conduit adapted and configured to gradually adjust a pressure drop thereacross and thus a flow rate of fuel flowing therethrough. The pulsating valve portion is in fluid connection with the supply conduit, in parallel with the proportional valve portion, and is adapted and configured to rapidly adjust a pressure drop thereacross and thus a flow rate of fuel flowing therethrough.

Abstract: A method of actively controlling pattern factor in a gas turbine engine includes the steps of issuing fuel into a combustion chamber of a gas turbine engine through one or more circumferentially disposed fuel injectors, determining an initial circumferential pattern factor in the combustion chamber, and adjusting fuel flow through one or more selected fuel injectors based on the initial circumferential pattern factor, to yield a modified circumferential pattern factor in the combustion chamber. The step of determining the circumferential pattern factor can include the steps of detecting a chemiluminescent signature within the combustor, correlating the chemiluminescent signature to an equivalence ratio, and computing the initial circumferential pattern factor based on the equivalence ratio.

Abstract: A feed arm for a multiple circuit fuel injector of a gas turbine engine. The feed arm includes an elongated tubular sleeve having a central bore with an interior wall defining an inner diameter, and an elongated fuel tube positioned within the bore of the tubular sleeve. The fuel tube includes a tubular wall defining an outer diameter, which is substantially equal to the inner diameter of the central bore. A primary fuel flow passage is formed within the tubular wall of the fuel tube and bounded by the interior wall of the tubular sleeve, and the primary fuel flow passage circumferentially extends around the fuel tube at least once along the axial length of the fuel tube. A secondary fuel flow passage extends through a central portion of the fuel tube, and the fuel tube is configured to facilitate heat transfer by conduction and/or convection.