Abstract: A pilot fuel injector is provided for a fuel nozzle of a gas turbine engine. The pilot fuel injector can include an axially-elongated, inner pilot centerbody wall extending from an upstream end to a downstream end, with the axially-elongated, inner pilot centerbody wall having a diverging-converging orientation with respect to a centerline axis to define a hollow tube having an upstream diameter, a throat, and a downstream diameter such that the throat has an inner diameter that is less than both of the upstream diameter and the downstream diameter. The pilot fuel injector also includes a center air circuit positioned at the upstream end, and an annular fuel passage defining the downstream end and intersecting with the centerbody wall at a pilot fuel metering orifice. A pilot fuel film surface is downstream from the annular fuel passage.

Abstract: A gas turbine engine includes a combustion section, the combustion section including a plurality of fuel nozzles. A fuel delivery system for the gas turbine engine includes a feed tube and a fuel manifold fluidly connected to the feed tube for receiving fuel from the feed tube. The fuel delivery system also includes a pigtail fuel line fluidly connected to the fuel manifold and configured to fluidly connect to a fuel nozzle of the plurality of fuel nozzles when the fuel delivery system is installed in the gas turbine engine. In order to reduce an amount of hydraulic instability of a fuel flow through the fuel delivery system, at least one of the fuel manifold or the pigtail fuel line includes a means for damping a hydraulic instability within the fuel delivery system.

Abstract: A fuel nozzle is provided for a gas turbine engine, and can include a pilot fuel injector having an axially-elongated, inner pilot centerbody wall and an outer pilot centerbody wall, with the axially-elongated, inner pilot centerbody wall extending from an upstream end to an annular fuel passage defining the downstream end of the pilot fuel injector. The fuel passage intersects with the inner pilot centerbody wall at a pilot fuel metering orifice. The fuel nozzle also includes a pilot fuel film surface downstream from the annular fuel passage and an annular splitter surrounding the pilot fuel injector. The annular splitter comprises, in axial sequence: an upstream section, a splitter throat having a diameter that is larger than a downstream diameter defined by the pilot fuel film surface, and a downstream diverging surface having an average diverging angle of about 24° to about 40° in relation to a centerline axis.

Abstract: A pilot fuel injector is provided for a fuel nozzle of a gas turbine engine. The pilot fuel injector can include an axially-elongated, inner pilot centerbody wall extending from an upstream end to a downstream end, with the axially-elongated, inner pilot centerbody wall having a diverging-converging orientation with respect to a centerline axis to define a hollow tube having an upstream diameter, a throat, and a downstream diameter such that the throat has an inner diameter that is less than both of the upstream diameter and the downstream diameter. The pilot fuel injector also includes a center air circuit positioned at the upstream end, and an annular fuel passage defining the downstream end and intersecting with the centerbody wall at a pilot fuel metering orifice. A pilot fuel film surface is downstream from the annular fuel passage.

Abstract: In one aspect, a fuel supply system may include a fuel injector having a primary and a secondary pilot fuel nozzle in fluid communication with a primary and a secondary fuel circuit, respectively, and a main fuel nozzle in fluid communication with a main fuel circuit. The fuel injector may also define a by-pass fuel circuit connected between the primary circuit and the secondary circuit and/or the main circuit. The system may also include a primary fuel manifold configured to be fluidly connected to the primary pilot fuel nozzle via the primary fuel circuit. Moreover, the system may include a by-pass valve provided in operative association with the by-pass fuel circuit. The by-pass valve may be configured to be opened such that a portion of the fuel flowing through the primary circuit from the primary fuel manifold is directed to the secondary circuit and/or the main circuit.

Abstract: A pilot fuel injector tip includes concentric primary and secondary pilot fuel nozzles having a circular primary exit axially aft and downstream of an annular secondary exit respectively. A fuel nozzle assembly includes a pilot swirler flowpath section having an annular inwardly tapering conical flowpath section surrounding primary and secondary exits. An inwardly tapering conical wall section radially inwardly bounding flowpath section defines a conical surface. Exits are located at or axially forward or upstream of the conical surface. An annular secondary fuel supply passage in secondary pilot fuel nozzle includes a secondary fuel swirler with an array of helical spin slots that may have rectangular cross sections. A chamfered leading edge of an annular wall section disposed between an outer pilot swirler and an inlet to an injector cooling flowpath surrounding the second pilot swirler includes a radially inwardly facing conical chamfered surface for deflecting dirt from cooling flowpath.

Abstract: A method for actively controlling fuel flow from a fuel pump to a mixer assembly of a gas turbine engine combustor, where the mixer assembly includes a pilot mixer and a main mixer. The pilot mixer further includes an annular pilot housing having a hollow interior, a primary fuel injector mounted in the pilot housing and adapted for dispensing droplets of fuel to the hollow interior of the pilot housing, a plurality of axial swirlers positioned upstream from the primary fuel injector. The fuel flow control apparatus further includes: at least one sensor for detecting dynamic pressure in the combustor; a fuel nozzle; and, a system for controlling fuel flow supplied by the fuel nozzle through the valves. The fuel nozzle includes: a feed strip with a plurality of circuits for providing fuel to the pilot mixer and the main mixer; and, a plurality of valves associated with the fuel nozzle and in flow communication with the feed strip thereof.

Abstract: A gas turbine engine fuel nozzle assembly includes a pilot fuel injector tip substantially centered about a centerline axis in an annular pilot inlet to a pilot mixer. A cross over arm extends across inlet to tip. Arm includes an arm fairing surrounding at least one fuel transfer tube to tip. A pilot nose cap is at an upstream end of tip. At least one of the cross over arm and the pilot nose cap includes a rounded forebody followed by a straight afterbody. Rounded forebody of pilot nose cap includes a substantially rounded dome extending forwardly from a rounded nose base and straight afterbody includes a substantially cylindrical nose afterbody parallel to a pilot nose centerline normal to nose base. An arm fairing surrounding fuel transfer tubes to tip includes rounded leading and trailing edges and a rectangular middle section therebetween having flat first and second sides.

Abstract: A gas turbine engine fuel nozzle assembly includes a pilot fuel injector tip substantially centered about a centerline axis in an annular pilot inlet to a pilot mixer. A cross over arm extends across inlet to tip. Arm includes an arm fairing surrounding at least one fuel transfer tube to tip. A pilot nose cap is at an upstream end of tip. At least one of the cross over arm and the pilot nose cap includes a rounded forebody followed by a straight afterbody. Rounded forebody of pilot nose cap includes a substantially rounded dome extending forwardly from a rounded nose base and straight afterbody includes a substantially cylindrical nose afterbody parallel to a pilot nose centerline normal to nose base. An arm fairing surrounding fuel transfer tubes to tip includes rounded leading and trailing edges and a rectangular middle section therebetween having flat first and second sides.

Abstract: A pilot fuel injector tip includes concentric primary and secondary pilot fuel nozzles having a circular primary exit axially aft and downstream of an annular secondary exit respectively. A fuel nozzle assembly includes a pilot swirler flowpath section having an annular inwardly tapering conical flowpath section surrounding primary and secondary exits. An inwardly tapering conical wall section radially inwardly bounding flowpath section defines a conical surface. Exits are located at or axially forward or upstream of the conical surface. An annular secondary fuel supply passage in secondary pilot fuel nozzle includes a secondary fuel swirler with an array of helical spin slots that may have rectangular cross sections. A chamfered leading edge of an annular wall section disposed between an outer pilot swirler and an inlet to an injector cooling flowpath surrounding the second pilot swirler includes a radially inwardly facing conical chamfered surface for deflecting dirt from cooling flowpath.

Abstract: A fuel nozzle assembly includes a chamfered leading edge of an annular wall section disposed between an outer pilot swirler and an inlet to an injector cooling flowpath surrounding the second pilot swirler. A radially inwardly facing conical chamfered surface of the chamfered leading edge deflects dirt from cooling flowpath.

Abstract: A mixer for a gas turbine engine combustor includes: (a) a primary fuel injector with upstream and downstream ends, the primary fuel injector including: (1) a hollow central portion configured to pass a first air stream; (2) an annular fuel passage at the downstream end, configured to discharge an annular first fuel stream surrounding the first air stream; (b) an annular splitter surrounding the primary fuel injector, configured to pass a second air stream surrounding the first fuel stream; (c) an annular first housing surrounding the splitter, and having an exit positioned axially downstream of the primary fuel injector and the splitter; and (d) fuel injection ports disposed in an array outside the first housing, and disposed in communication with a fuel supply and positioned to discharge a second fuel stream into a third air stream at a position axially upstream of the exit of the first housing.

Abstract: An apparatus for actively controlling fuel flow from a fuel pump to a mixer assembly of a gas turbine engine combustor, where the mixer assembly includes a pilot mixer and a main mixer. The pilot mixer further includes an annular pilot housing having a hollow interior, a primary fuel injector mounted in the pilot housing and adapted for dispensing droplets of fuel to the hollow interior of the pilot housing, a plurality of axial swirlers positioned upstream from the primary fuel injector. The fuel flow control apparatus further includes: at least one sensor for detecting dynamic pressure in the combustor; a fuel nozzle; and, a system for controlling fuel flow supplied by the fuel nozzle through the valves. The fuel nozzle includes: a feed strip with a plurality of circuits for providing fuel to the pilot mixer and the main mixer; and, a plurality of valves associated with the fuel nozzle and in flow communication with the feed strip thereof.

Abstract: An Active Combustion Control System and method provides for monitoring combustor pressure and modulating fuel to a gas turbine combustor to prevent combustion dynamics and/or flame extinguishments. The system includes an actuator, wherein the actuator periodically injects pulsed fuel into the combustor. The apparatus also includes a sensor connected to the combustion chamber down stream from an inlet, where the sensor generates a signal detecting the pressure oscillations in the combustor. The apparatus controls the actuator in response to the sensor. The apparatus prompts the actuator to periodically inject pulsed fuel into the combustor at a predetermined sympathetic frequency and magnitude, thereby controlling the amplitude of the pressure oscillations in the combustor by modulating the natural oscillations.

Abstract: A mixer for a gas turbine engine combustor includes: (a) a primary fuel injector with upstream and downstream ends, the primary fuel injector including: (1) a hollow central portion configured to pass a first air stream; (2) an annular fuel passage at the downstream end, configured to discharge an annular first fuel stream surrounding the first air stream; (b) an annular splitter surrounding the primary fuel injector, configured to pass a second air stream surrounding the first fuel stream; (c) an annular first housing surrounding the splitter, and having an exit positioned axially downstream of the primary fuel injector and the splitter; and (d) fuel injection ports disposed in an array outside the first housing, and disposed in communication with a fuel supply and positioned to discharge a second fuel stream into a third air stream at a position axially upstream of the exit of the first housing.

Abstract: A mixer assembly for a gas turbine engine, including: a primary fuel injector having a central axis for injecting a primary fuel spray into a primary air stream, wherein fuel is provided at a desired rate and droplets of the fuel spray are within a desired size range; a secondary fuel injector positioned radially outwardly of the primary fuel injector for injecting a secondary fuel spray into a secondary air stream spaced radially outwardly of and surrounding the primary air stream; and, a primary air jet positioned between the primary fuel injector and the secondary fuel injector to direct a portion of an incoming air stream between the primary air stream and the secondary air stream.

Abstract: An apparatus for actively controlling fuel flow from a fuel pump to a mixer assembly of a gas turbine engine combustor, where the mixer assembly includes a pilot mixer and a main mixer. The pilot mixer further includes an annular pilot housing having a hollow interior, a primary fuel injector mounted in the pilot housing and adapted for dispensing droplets of fuel to the hollow interior of the pilot housing, a plurality of axial swirlers positioned upstream from the primary fuel injector. The fuel flow control apparatus further includes: at least one sensor for detecting dynamic pressure in the combustor; a fuel nozzle; and, a system for controlling fuel flow supplied by the fuel nozzle through the valves. The fuel nozzle includes: a feed strip with a plurality of circuits for providing fuel to the pilot mixer and the main mixer; and, a plurality of valves associated with the fuel nozzle and in flow communication with the feed strip thereof.

Abstract: A gas turbine engine fuel nozzle assembly has concentric primary and secondary pilot fuel nozzles with circular primary and annular secondary exits respectively and a main fuel nozzle spaced radially outwardly of the pilot fuel nozzles. The primary and secondary pilot fuel nozzles include conical primary and secondary exit holes respectively. The secondary pilot fuel nozzle is located directly adjacent to and surrounding the primary pilot fuel nozzle. Alternatively the secondary pilot fuel nozzle may be radially spaced apart from the primary pilot fuel nozzle. A fuel injector having a hollow stem may be used to support the fuel nozzle assembly. A first pilot swirler may be located radially outwardly of and adjacent to the dual orifice pilot fuel injector tip, a second pilot swirler located radially outwardly of the first swirler, and a splitter radially positioned between the first and second pilot swirlers.

Abstract: A mixer assembly for use in a combustion chamber of a gas turbine engine includes a pilot mixer, a main mixer and a centerbody positioned between the pilot mixer and the main mixer. The pilot mixer includes an annular pilot housing having a hollow interior and a pilot fuel nozzle mounted in the housing and adapted for dispensing droplets of fuel to the hollow interior of the pilot housing. The main mixer includes: a main housing surrounding the pilot housing and defining an annular cavity; a plurality of fuel injection ports for introducing fuel into the annular cavity; and, a swirler arrangement including at least one swirler positioned upstream from the fuel injection ports, wherein each swirler of the arrangement has a plurality of vanes for swirling air traveling through such swirler to mix air and the droplets of fuel dispensed by the fuel injection ports.

Abstract: An Active Combustion Control System and method provides for monitoring combustor pressure and modulating fuel to a gas turbine combustor to prevent combustion dynamics and/or flame extinguishments. The system includes an actuator, wherein the actuator periodically injects pulsed fuel into the combustor. The apparatus also includes a sensor connected to the combustion chamber down stream from an inlet, where the sensor generates a signal detecting the pressure oscillations in the combustor. Lastly, the apparatus includes means for controlling the actuator in response to the sensor. The means for controlling prompts the actuator to periodically inject pulsed fuel into the combustor at a predetermined sympathetic frequency and magnitude, thereby controlling the amplitude of the pressure oscillations in the combustor by modulating the natural oscillations.