Mixer assembly for combustor of a gas turbine engine having a main mixer with improved fuel penetration

Abstract

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 positioned between the pilot mixer and 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 having an upstream end and a downstream end including an upstream wall, an outer wall and an inner wall; a plurality of fuel injection ports for introducing fuel into the cavity, with the fuel injection ports being circumferentially spaced at a designated axial location of the inner wall of the annular cavity; and a swirler arrangement including at least one swirler in flow communication with the annular cavity, the swirler being incorporated into the outer wall of the annular cavity and extending from an upstream end to a downstream end, 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. The main housing further includes a first plurality of passages oriented to provide air jets in a substantially axial direction into the annular cavity and a second plurality of passages oriented to provide air jets in a substantially radial direction into the annular cavity

1 . A mixer assembly for use in a combustion chamber of a gas turbine engine, comprising: 
 (a) a pilot mixer including an annular pilot housing having a hollow interior and a pilot fuel nozzle mounted in said housing and adapted for dispensing droplets of fuel to said hollow interior of said pilot housing;    (b) a main mixer including: 
 (1) a main housing surrounding said pilot housing and defining an annular cavity having an upstream end and a downstream end, said annular cavity including an upstream wall; an outer wall and an inner wall;  
 (2) a plurality of fuel injection ports for introducing fuel into said annular cavity, said fuel injection ports being circumferentially spaced at a designated axial location of said inner wall of said annular cavity; and,  
 (3) a swirler arrangement including at least one swirler in flow communication with said annular cavity, said swirler being incorporated into said outer wall of said annular cavity and extending from an upstream end to a downstream end, wherein each swirler of said arrangement has a plurality of vanes for swirling air traveling through such swirler to mix air and said droplets of fuel dispensed by said fuel injection ports; and,  
   (c) a fuel manifold positioned between said pilot mixer and said main mixer, wherein said plurality of fuel injection ports for introducing fuel into said main mixer cavity are in flow communication with said fuel manifold.    
   
   
       2 . The mixer assembly of  claim 1 , said upstream wall of said annular cavity including a first plurality of circumferentially spaced passages in flow communication with compressed air.  
   
   
       3 . The mixer assembly of  claim 2 , wherein said first passages are oriented to provide air jets in a substantially axial direction into said annular cavity.  
   
   
       4 . The mixer assembly of  claim 3 , wherein said first passages are oriented to provide a designated swirl to said air jets in said annular cavity.  
   
   
       5 . The mixer assembly of  claim 4 , wherein said designated swirl of said air jets is at an angle in a range of about 25° to about 60° with respect to a centerline axis through said mixer assembly.  
   
   
       6 . The mixer assembly of  claim 4 , wherein said air jets are swirled in a direction opposite air swirled by said swirler.  
   
   
       7 . The mixer assembly of  claim 2 , said upstream wall of said annular cavity further including a second plurality of passages in flow communication with compressed air.  
   
   
       8 . The mixer assembly of  claim 7 , wherein said second passages are oriented to provide air jets in a substantially radial direction into said annular cavity.  
   
   
       9 . The mixer assembly of  claim 8 , wherein said second passages are oriented to provide a designated swirl to said air jets in said annular cavity.  
   
   
       10 . The mixer assembly of  claim 9 , wherein said designated swirl of said air jets is at an angle in a range of about 25° to about 60° with respect to an axis substantially perpendicular to a centerline axis through said mixer assembly.  
   
   
       11 . The mixer assembly of  claim 9 , wherein said air jets are swirled in a direction opposite air swirled by said swirler.  
   
   
       12 . The mixer assembly of  claim 1 , wherein said fuel injection ports are located immediately downstream of a ramp portion in said inner wall of said annular cavity.  
   
   
       13 . The mixer assembly of  claim 1 , wherein said fuel injection ports are located immediately upstream of a ramp portion in said inner wall of said annular cavity.  
   
   
       14 . The mixer assembly of  claim 1 , wherein said fuel injection ports are spaced circumferentially around said annular cavity.  
   
   
       15 . The mixer assembly of  claim 14 , further comprising a plurality of purge holes between each said fuel injection port in flow communication with compressed air.  
   
   
       16 . The mixer assembly of  claim 1 , said fuel injection ports further comprising a post member having an inner passage in flow communication therewith.  
   
   
       17 . The mixer assembly of  claim 16 , wherein said post member of said fuel injection ports extends at least even with an outer surface of said inner wall of said annular cavity.  
   
   
       18 . The mixer assembly of  claim 1 , said swirler arrangement further comprising at least one swirler oriented substantially radially to a centerline axis through said mixer assembly having a designated axial length.  
   
   
       19 . The mixer assembly of  claim 18 , wherein said injection ports are located within said axial length of said swirler.  
   
   
       20 . The mixer assembly of  claim 1 , said swirler arrangement further comprising at least one swirler oriented at an acute angle to a centerline axis through said mixer assembly.  
   
   
       21 . The mixer assembly of  claim 1 , said swirler arrangement further comprising at least one swirler oriented substantially parallel to a centerline axis through said mixer assembly.  
   
   
       22 . The mixer assembly of  claim 1 , wherein fuel droplets from said fuel injection ports are able to penetrate to a designated position within said annular cavity.  
   
   
       23 . The mixer assembly of  claim 7 , wherein air injected through said first and second plurality of passages is in a range of about 15% to about 30% of total air flowing through said main mixer.  
   
   
       24 . A mixer assembly for use in a combustion chamber of a gas turbine engine, comprising: 
 (a) a pilot mixer including an annular pilot housing having a hollow interior and a pilot fuel nozzle mounted in said housing and adapted for dispensing droplets of fuel to said hollow interior of said pilot housing;    (b) a main mixer including: 
 (1) a main housing surrounding said pilot housing and defining an annular cavity, said main housing further comprising: 
 (a) a ramp portion positioned at an upstream portion of said annular cavity;  
 (b) an upstream wall including a first plurality of passages and a second plurality of passages in flow communication with an air supply, wherein said first passages are oriented to provide air jets in a substantially axial direction into said annular cavity and said second passages are oriented to provide air jets in a substantially radial direction into said annular cavity;  
 
 (2) a plurality of fuel injection ports for introducing fuel into said annular cavity, wherein said fuel injection ports are positioned adjacent said ramp portion of said annular cavity; and,  
 (3) a swirler arrangement including at least one swirler positioned upstream from said fuel injection ports, wherein each swirler of said arrangement has a plurality of vanes for swirling air traveling through such swirler to mix air and said droplets of fuel dispensed by said fuel injection ports; and,  
   (c) a fuel manifold positioned between said pilot mixer and said main mixer, wherein said plurality of fuel injection ports for introducing fuel into said main mixer cavity are in flow communication with said fuel manifold.