Fuel injection assembly having partial direct injectors

Abstract

A fuel injection assembly for a combustor of a gas turbine includes a fuel injector configured to couple to an outer sleeve of the combustor. A boss is configured to couple to a combustion liner of the combustor at a position axially and circumferentially aligned with the fuel injector. An insert is removably coupled to the boss. The insert includes a flange portion and an annular wall portion extending from the flange portion and defining a mixing channel. The insert defines a plurality of partial direct injectors spaced apart from one another and disposed about the mixing channel. A combustor including such a fuel injection assembly is also provided.

What is claimed is: 
     
         1 . A fuel injection assembly for a combustor of a gas turbine, the fuel injection assembly comprising:
 a fuel injector configured to couple to an outer sleeve of the combustor;   a boss configured to couple to a combustion liner of the combustor at a position axially and circumferentially aligned with the fuel injector; and   an insert removably coupled to the boss, the insert comprising a flange portion, an annular wall portion extending from the flange portion, the annular wall portion defining a mixing channel, wherein the insert defines a plurality of partial direct injectors spaced apart from one another and disposed about the mixing channel.   
     
     
         2 . The fuel injection assembly as in  claim 1 , wherein at least one partial direct injector of the plurality of partial direct injectors is defined in the flange portion of the insert. 
     
     
         3 . The fuel injection assembly as in  claim 1 , wherein at least one partial direct injector of the plurality of partial direct injectors is defined in the annular wall portion of the insert. 
     
     
         4 . The fuel injection assembly as in  claim 1 , wherein the insert defines an air supply circuit and a fuel supply circuit each fluidly coupled to the plurality of partial direct injectors. 
     
     
         5 . The fuel injection assembly as in  claim 4 , wherein the air supply circuit includes an air inlet passage, an air plenum, and a plurality of air outlet passages each extending from the air plenum to a respective partial direct injector of the plurality of partial direct injectors. 
     
     
         6 . The fuel injection assembly as in  claim 5 , wherein the air plenum is annular. 
     
     
         7 . The fuel injection assembly as in  claim 1 , wherein each partial direct injector extends to an outlet on a radially inner surface of the flange portion of the insert. 
     
     
         8 . The fuel injection assembly as in  claim 1 , wherein each partial direct injector is defined in the insert by a boundary surface, and wherein the boundary surface includes a cylindrical portion and a tapering portion. 
     
     
         9 . The fuel injection assembly as in  claim 8 , wherein an air outlet passage of an air supply circuit extends to the tapering portion of the boundary surface. 
     
     
         10 . The fuel injection assembly as in  claim 9 , wherein a fuel inlet passage of a fuel supply circuit extends to the partial direct injector generally perpendicularly to the air outlet passage. 
     
     
         11 . A combustor comprising:
 at least one fuel nozzle;   a combustion liner extending downstream from the fuel nozzle;   an outer sleeve spaced apart from and surrounding the combustion liner such that an annulus is defined therebetween; and   a fuel injection assembly disposed downstream from the at least one fuel nozzle, the fuel injection assembly comprising:   a fuel injector coupled to the outer sleeve of the combustor;   a boss coupled to the combustion liner of the combustor, the boss being axially and circumferentially aligned with the fuel injector; and   an insert removably coupled to the boss, the insert comprising a flange portion, an annular wall portion extending from the flange portion, the annular wall portion defining a mixing channel, wherein the insert defines a plurality of partial direct injectors spaced apart from one another and disposed about the mixing channel.   
     
     
         12 . The combustor as in  claim 11 , wherein at least one partial direct injector of the plurality of partial direct injectors is defined in the flange portion of the insert. 
     
     
         13 . The combustor as in  claim 11 , wherein at least one partial direct injector of the plurality of partial direct injectors is defined in the annular wall portion of the insert. 
     
     
         14 . The combustor as in  claim 11 , wherein the insert defines an air supply circuit and a fuel supply circuit each fluidly coupled to the plurality of partial direct injectors. 
     
     
         15 . The combustor as in  claim 14 , wherein the air supply circuit includes an air inlet passage, an air plenum, and a plurality of air outlet passages each extending from the air plenum to a respective partial direct injector of the plurality of partial direct injectors. 
     
     
         16 . The combustor as in  claim 15 , wherein the air plenum is annular. 
     
     
         17 . The combustor as in  claim 11 , wherein each partial direct injector extends to an outlet on a radially inner surface of the flange portion of the insert. 
     
     
         18 . The combustor as in  claim 11 , wherein each partial direct injector is defined in the insert by a boundary surface, and wherein the boundary surface includes a cylindrical portion and a tapering portion. 
     
     
         19 . The combustor as in  claim 18 , wherein an air outlet passage of an air supply circuit extends to the tapering portion of the boundary surface. 
     
     
         20 . The combustor as in  claim 19 , wherein a fuel inlet passage of a fuel supply circuit extends to the partial direct injector generally perpendicularly to the air outlet passage.