초록 ▼

A mixer assembly for use in a combustion chamber of a gas turbine engine includes a pilot mixer, a main mixer, and a fuel manifold. The pilot mixer includes: an annular pilot housing having a hollow interior, a primary fuel injector mounted in the pilot housing, a plurality of axial swirlers positio

A mixer assembly for use in a combustion chamber of a gas turbine engine includes a pilot mixer, a main mixer, and a fuel manifold. The pilot mixer includes: an annular pilot housing having a hollow interior, a primary fuel injector mounted in the pilot housing, a plurality of axial swirlers positioned upstream from the primary fuel injector, and a plurality of secondary fuel injection ports for introducing fuel into 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, and at least one swirler positioned upstream from the plurality of fuel injection ports. The fuel manifold is in flow communication with the plurality of secondary fuel injection ports in the pilot mixer and the plurality of fuel injection ports in the main mixer.

대표청구항 ▼

What is claimed is: 1. A mixer assembly for use in a combustion chamber of a gas turbine engine, said assembly comprising: (a) a pilot mixer having multiple stages including: (1) an annular pilot housing having a hollow interior; (2) a primary fuel injector mounted in said pilot housing and adapted

What is claimed is: 1. A mixer assembly for use in a combustion chamber of a gas turbine engine, said assembly comprising: (a) a pilot mixer having multiple stages including: (1) an annular pilot housing having a hollow interior; (2) a primary fuel injector mounted in said pilot housing and adapted for dispensing droplets of fuel to said hollow interior of said pilot housing; (3) a plurality of axial swirlers positioned upstream from said primary fuel injector, each of said plurality of swirlers having a plurality of vanes for swirling air traveling through the respective swirler to mix air and the droplets of fuel dispensed by said primary fuel injector; and, (4) a plurality of secondary fuel injection ports for introducing fuel into said hollow interior of said pilot housing, wherein a fuel supply path to the secondary fuel injection ports is independent from a fuel supply path to the primary fuel injector; and, (b) a main mixer including: (1) a main housing surrounding said pilot housing and defining an annular cavity; (2) a plurality of fuel injection ports for introducing fuel into said cavity; and, (3) at least one swirler positioned upstream from said plurality of fuel injection ports, each of said main mixer swirlers having a plurality of vanes for swirling air traveling through the respective swirler to mix air and the droplets of fuel dispensed by said main mixer fuel injection ports; and, (c) a fuel manifold in flow communication with said plurality of secondary fuel injection ports in said pilot mixer and said plurality of fuel injection ports in said main mixer. 2. The mixer assembly of claim 1, said pilot mixer further comprising: (a) a first axial swirler positioned upstream from said primary fuel injector having a plurality of vanes for swirling air traveling therethrough; (b) a second axial swirler positioned upstream from said primary fuel injector and radially outside said first axial swirler having a plurality of vanes for swirling air traveling therethrough; and, (c) a splitter positioned between said first and second axial swirlers and extending downstream to a venturi portion. 3. The mixer assembly of claim 2, wherein said second swirler is configured to direct air toward an inner surface of said pilot housing. 4. The mixer assembly of claim 3, wherein vanes in said second swirler have an angle in a range of about 30° to about 60° with respect to a centerline axis through said pilot housing. 5. The mixer assembly of claim 1, wherein said secondary fuel injection ports of said pilot mixer are circumferentially spaced within a designated plane intersecting a centerline axis through said pilot housing. 6. The mixer assembly of claim 2, wherein said secondary fuel injection ports of said pilot mixer are positioned downstream of said splitter. 7. The mixer assembly of claim 2, wherein said secondary fuel injection ports of said pilot mixer are positioned substantially within a plane at a downstream end of said splitter. 8. The mixer assembly of claim 2, wherein said secondary fuel injection ports of said pilot mixer are positioned upstream of an aft end for said splitter. 9. The mixer assembly of claim 1, wherein said secondary fuel injection ports of said pilot mixer are oriented substantially perpendicular to a centerline axis through said pilot housing. 10. The mixer assembly of claim 1, wherein said secondary fuel injection ports of said pilot mixer are oriented so as to be angled toward an upstream end of said pilot housing. 11. The mixer assembly of claim 1, wherein said secondary fuel injection ports of said pilot mixer are oriented so as to be angled toward a downstream end of said pilot housing. 12. The mixer assembly of claim 1, wherein said secondary fuel injection ports of said pilot mixer are formed in a flared portion of said pilot housing. 13. The mixer assembly of claim 1, wherein fuel is injected from said secondary fuel injection ports of said pilot mixer into said downstream end of said pilot mixer at a designated cycle point for said gas turbine engine. 14. The mixer assembly of claim 1, wherein fuel is injected from said secondary fuel injection ports of said pilot mixer into said downstream end of said pilot mixer when compressor discharge air of said gas turbine engine is at a designated temperature. 15. The mixer assembly of claim 1, wherein fuel is injected from said primary fuel injector at a faster rate than fuel injected from said secondary fuel injection ports of said pilot mixer. 16. The mixer assembly of claim 1, wherein fuel is injected from said primary fuel injector and said secondary fuel injection ports of said pilot mixer at substantially the same rate. 17. The mixer assembly of claim 1, wherein fuel is injected from said secondary fuel injection ports of said pilot mixer at a faster rate than fuel injected from said primary fuel injector. 18. The mixer assembly of claim 1, wherein said pilot mixer is able to power said gas turbine engine up to approximately 30% of maximum thrust when fuel is provided only from said primary fuel injector. 19. The mixer assembly of claim 1, wherein said pilot mixer is able to power said gas turbine engine up to approximately 70% of maximum thrust when fuel is provided by said primary fuel injector and said secondary fuel injection ports. 20. The mixer assembly of claim 1, further comprising a passage surrounding each secondary fuel injection port of said pilot mixer in flow communication with an air supply. 21. The mixer assembly of claim 20, further comprising a swirler member positioned within said passage so as to swirl air flowing therethrough. 22. The mixer assembly of claim 1, wherein an air flow rate through said pilot mixer is at least about 10%. 23. The mixer assembly of claim 1, wherein an air flow rate through said pilot mixer is no greater than about 30%. 24. A method of operating a gas turbine engine combustor having a pilot mixer with multiple stages and a main mixer, wherein said pilot mixer includes an annular pilot housing having a hollow interior, a primary fuel injector mounted in said pilot housing and adapted for dispensing droplets of fuel to said hollow interior of said pilot housing, a plurality of axial swirlers positioned upstream from said print fuel injector, wherein each of said plurality of swirlers has a plurality of vanes for swirling air traveling through the respective swirler to mix air and the droplets of fuel dispensed by said primary fuel injector, and a plurality of secondary fuel injection ports for introducing fuel into said hollow interior of said pilot housing, said method comprising the following steps: (a) providing air through said pilot mixer swirlers at a designated air flow rate; (b) providing fuel through said primary fuel injector; and, (c) providing fuel through said secondary fuel injection ports of said pilot mixer during predetermined conditions; (d) providing air through said main mixer swirlers at a designated air flow rate; (e) providing fuel through fuel injection ports of said main mixer during predetermined conditions. 25. The method of claim 24, wherein fuel is provided through said secondary fuel injection ports of said pilot mixer while fuel is provided through said primary fuel injector. 26. The method of claim 24, wherein fuel is provided through said secondary fuel injection ports of said pilot mixer when fuel is not provided through said primary fuel injector. 27. A combustor for a gas turbine engine, comprising: (a) an outer liner; (b) an inner liner spaced radially from said outer liner so as to form a combustion chamber therebetween; (c) a dome positioned at an upstream end of said combustion chamber; (d) a pilot mixer having multiple stages including: (1) an annular pilot housing having a hollow interior; (2) a primary fuel injector mounted in said pilot housing and adapted for dispensing droplets of fuel to said hollow interior of said pilot housing; (3) a plurality of axial swirlers positioned upstream from said primary fuel injector, each of said plurality of swirlers having a plurality of vanes for swirling air traveling through the respective swirler to mix air and the droplets of fuel dispensed by said primary fuel injector; and, (4) a plurality of secondary fuel injection ports for introducing fuel into said hollow interior of said pilot housing, wherein a fuel supply oath to the secondary fuel injection ports is independent from a fuel supply oath to the primary fuel injector; and, (e) a main mixer including: (1) a main housing surrounding said pilot mixer and defining an annular cavity; (2) a plurality of fuel injection ports for introducing fuel into said cavity; and, (3) at least one swirler positioned upstream from said plurality of fuel injection ports, each of said main mixer swirlers having a plurality of vanes for swirling air traveling through the respective swirler to mix air and the droplets of fuel dispensed by said main mixer fuel injection ports; and, (f) a fuel manifold in flow communication with said plurality of secondary fuel injection ports in said pilot mixer and said plurality of fuel injection ports in said main mixer.