Reducing film scrubbing in a combustor

Abstract

An apparatus, system, and method of reducing film cooling scrubbing in a combustor are provided. The apparatus includes a combustor liner that includes a field of a plurality of sparsely-spaced film holes that extend through the combustor liner wherein the field includes a boundary. The combustor liner also includes a patch of relatively more densely-spaced shield holes that extend through the combustor liner at specific predetermined locations within the boundary of the field.

What is claimed is: 
     
         1 . A combustor liner comprising:
 a field of a plurality of sparsely-spaced film holes that extend through said liner, said field having a boundary; and   a patch of relatively more densely-spaced shield holes that extend through said combustor liner at specific predetermined locations within said boundary of said field.   
     
     
         2 . The combustor liner of  claim 1 , wherein said plurality of sparsely-spaced film holes are spaced approximately equidistant a first distance with respect to each other. 
     
     
         3 . The combustor liner of  claim 1 , wherein said densely-spaced shield holes are spaced approximately equidistant a second distance with respect to each other. 
     
     
         4 . The combustor liner of  claim 1 , wherein said plurality of sparsely-spaced film holes are spaced part a first distance with respect to each other, said densely-spaced shield holes are spaced apart a second distance with respect to each other, said second distance different than said first distance. 
     
     
         5 . The combustor liner of  claim 1 , wherein said plurality of sparsely-spaced film holes are spaced part a first distance with respect to each other, said densely-spaced shield holes are spaced apart a second distance with respect to each other, said second distance less than said first distance. 
     
     
         6 . The combustor liner of  claim 1 , wherein said plurality of sparsely-spaced film holes include a first cross-sectional area, said densely-spaced shield holes include a second cross-sectional area, said second cross-sectional area different than said first cross-sectional area. 
     
     
         7 . The combustor liner of  claim 1 , wherein at least some of said plurality of sparsely-spaced film holes comprise an oval cross-section. 
     
     
         8 . The combustor liner of  claim 1 , wherein at least some of said plurality of sparsely-spaced film holes comprise a diffuser exit. 
     
     
         9 . The combustor liner of  claim 1 , wherein said patch of relatively more densely-spaced shield holes excludes sparsely-spaced film holes within the patch. 
     
     
         10 . The combustor liner of  claim 1 , wherein said densely-spaced shield holes comprise a circular cross-section. 
     
     
         11 . A method of reducing film cooling scrubbing in a combustor, said method comprising:
 channeling a laminar flow of cooling fluid to a surface of a liner of the combustor, the combustor liner at least partially surrounding a combustion zone of the combustor;   directing a flow of a swirled fuel air mixture into the combustion zone, a centrifugal force of the flow of the swirled fuel air mixture driving a portion of the flow of the swirled fuel air mixture into one or more affected areas of the combustor liner; and   directing a flow of shield air through the combustor liner proximate the one or more affected areas.   
     
     
         12 . The method of  claim 11 , wherein channeling a laminar flow of cooling fluid to a surface of a liner of the combustor comprises channeling a flow of cooling fluid through sparsely-spaced film holes in the combustor liner. 
     
     
         13 . The method of  claim 11 , wherein directing a flow of shield air through the combustor liner comprises directing a flow of shield air to a surface of the combustor liner through holes having an approximately circular cross-section. 
     
     
         14 . The method of  claim 11 , wherein directing a flow of shield air comprises positioning a plurality of densely-spaced shield holes extending through the combustor liner proximate an area on the surface of the combustor liner where the swirled fuel air mixture will interact with the laminar flow of cooling fluid. 
     
     
         15 . The method of  claim 11 , further comprising changing a direction of the portion of the flow of the swirled fuel air mixture using a momentum of the flow of shield air. 
     
     
         16 . The method of  claim 11 , wherein directing a flow of shield air comprises directing a flow of shield air from a same source of air as the laminar flow of cooling fluid. 
     
     
         17 . A gas turbine engine system comprising a high pressure compressor, a combustor, and a high pressure turbine in a serial flow relationship, said combustor comprising:
 a field of a plurality of sparsely-spaced film holes that extend through a liner of said combustor, said field having a boundary; and   a contiguous patch of relatively more densely-spaced shield holes that extend through said combustor liner within said boundary of said field.   
     
     
         18 . The gas turbine engine system of  claim 17 , wherein said field of said plurality of sparsely-spaced film holes and said patch of relatively more densely-spaced shield holes are coupled in flow communication with a fluid discharge port of said high pressure compressor. 
     
     
         19 . The gas turbine engine system of  claim 17 , wherein said combustor further comprises a mixer assembly that includes a pilot mixer which is supplied with fuel during the entire engine operating cycle and a main mixer which is supplied with fuel only during increased power conditions of the engine operating cycle. 
     
     
         20 . The gas turbine engine system of  claim 17 , wherein said at least some of said plurality of sparsely-spaced film holes comprise diffusers at a surface of said combustor liner and said patch of relatively more densely-spaced shield holes comprise a circular cross-section.