Gas turbine combustor

Abstract

A gas turbine combustor includes a pilot burner, provided at a top portion of a combustion liner having a combustion chamber defined therein, and a main burner of a premixing type disposed adjacent an outer periphery thereof. The pilot burner is provided with an inflow passage, provided in an upstream end portion to allow the compressed air from a radially outer area into a radially inner area, a plurality of fuel supply holes for injecting the fuel into the inflow passage in a direction perpendicular to the flow of the compressed air, a premixing passage for guiding the air-fuel mixture from the inflow passage in an axially downstream direction while the compressed air and the fuel are mixed together, and a plurality of premixed air-fuel mixture injection holes for injecting the premixed air-fuel mixture from the premixing passage into the combustion chamber.

What is claimed is: 
     
         1 . A gas turbine combustor to mix a compressed air, fed from a compressor, with a fuel to burn a resultant air-fuel mixture to be supplied to a turbine, which combustor comprising:
 a pilot burner provided in a top portion of a combustion liner defining a combustion chamber therein,   a main burner of a premixing type located on an outer periphery side thereof, the pilot burner including:
 an inflow passage provided in an upstream end portion to allow the compressed air to inflow from a radially outer area into a radially inner area; 
 a plurality of fuel supply holes to inject the fuel into the inflow passage in a direction perpendicular to the flow of the compressed air; 
 a premixing passage to mix the compressed air and the fuel inflowed through the inflow passage and to guide the air-fuel mixture towards an axially downstream side; and 
 a plurality of premixed air-fuel mixture injection holes to inject the premixed air-fuel mixture from the premixing passage into the combustion chamber. 
   
     
     
         2 . The gas turbine combustor as claimed in  claim 1 , further comprising a fuel injection hole formed at a center portion of the pilot burner to inject a portion of a fuel for the pilot burner into the combustion chamber. 
     
     
         3 . The gas turbine combustor as claimed in  claim 2 , further comprising a carbon removal injection hole formed in the vicinity of a downstream side of the fuel injection hole to supply a portion of the premixed air-fuel mixture within the premixing passage. 
     
     
         4 . The gas turbine combustor as claimed in  claim 1 , wherein the premixing passage includes a speed increasing portion having a passage section that gradually reduces towards a downstream side. 
     
     
         5 . The gas turbine combustor as claimed in  claim 4 , further comprising a mixing facilitation member provided on an upstream side of the speed increasing portion in the premixing passage to facilitate a premixing by deflecting the premixed air-fuel mixture radially outwardly. 
     
     
         6 . The gas turbine combustor as claimed in  claim 1 , wherein the inflow passage has an annular inflow opening, the inflow passage including a plurality of guide pieces positioned radially inwardly of the annular inflow opening to guide the compressed air towards a center of the inflow passage. 
     
     
         7 . The gas turbine combustor as claimed in  claim 6 , wherein the fuel supply holes are arranged at portions between the neighboring guide pieces. 
     
     
         8 . The gas turbine combustor as claimed in  claim 1 , wherein the plurality of premixed air-fuel mixture injection holes include a plurality of first air-fuel mixture injection holes provided in a peripheral wall of a cylindrical body that forms an outer wall of the premixing passage and a plurality of second air-fuel mixture injection holes provided in a tip end portion of the pilot burner.