Impingement cooling of combustor liners

Abstract

A gas turbine engine may include an impingement cooled double-walled liner, having an inner liner and an outer liner, disposed around a combustion space of the turbine engine. The double-walled liner may extend from an upstream end to a downstream end. The gas turbine engine may also include a plurality of nozzles extending radially inwards through the outer liner to direct cooling air towards the inner liner. Each nozzle of the plurality of nozzles may extend radially inwards from a first distal end to a second proximal end. The plurality of nozzles may be arranged such that a radial gap between the second end of a nozzle and the outer liner decreases from the upstream end to the downstream end. The at least one nozzle of the plurality of nozzles may include multiple air holes at the second end.

What is claimed is: 
     
         1 . A gas turbine engine, comprising:
 an impingement cooled double-walled liner, including an inner liner and an outer liner, disposed around a combustion space of the turbine engine and extending from an upstream end to a downstream end; and   a plurality of nozzles extending radially inwards through the outer liner to direct cooling air towards the inner liner, each nozzle of the plurality of nozzles extending radially inwards from a first distal end to a second proximal end, the plurality of nozzles being arranged such that a radial gap between the second end of a nozzle and the outer liner decreases from the upstream end to the downstream end,
 wherein, at least one nozzle of the plurality of nozzles includes multiple air holes at the second end. 
   
     
     
         2 . The gas turbine engine of  claim 1 , wherein the at least one nozzle further includes a longitudinal axis extending from the first end to the second end and each air hole of the multiple air holes includes a central axis, the multiple air holes being symmetrically arranged about the longitudinal axis. 
     
     
         3 . The gas turbine engine of  claim 2 , wherein the central axis of each air hole is substantially parallel to the longitudinal axis. 
     
     
         4 . The gas turbine engine of  claim 2 , wherein the central axis of each air hole is inclined with respect to the longitudinal axis such that the cooling air exiting the at least one nozzle diverges. 
     
     
         5 . The gas turbine engine of  claim 1 , wherein the multiple air holes in the at least nozzle is arranged in a shower head pattern at the second end. 
     
     
         6 . The gas turbine engine of  claim 1 , wherein the second end of the at least one nozzle includes a projection that extends towards the inner liner. 
     
     
         7 . The gas turbine engine of  claim 6 , wherein the projection is centrally positioned on the second end and each air hole of the multiple air holes is symmetrically positioned about the projection. 
     
     
         8 . The gas turbine engine of  claim 1 , wherein the second end of the at least one nozzle is curved such that a central portion of the second end forms a proximal-most portion of the nozzle. 
     
     
         9 . The gas turbine engine of  claim 1 , wherein the radial gap decreases substantially linearly from the upstream end to the downstream end. 
     
     
         10 . A method of impingement cooling a double-walled combustor liner of a gas turbine engine, the double-walled liner extending from an upstream end to a downstream end and including an inner liner and an outer liner positioned radially outwards the inner liner, comprising:
 combusting a fuel in a combustor of the gas turbine engine; and   directing cooling air through a plurality of nozzles extending radially inwards through the outer liner to impinge upon and cool the inner liner, such that the cooling air exits the plurality of nozzles closer to the inner liner at the downstream end than at the upstream end, wherein the cooling air directed through at least one nozzle of the plurality of nozzles exit the at least nozzle through multiple air flow paths symmetrically arranged about a longitudinal axis of the at least one nozzle.   
     
     
         11 . The method of  claim 10 , wherein directing the cooling air includes directing the cooling air through the multiple air flow paths of the at least one nozzle such that the cooling air diverges. 
     
     
         12 . The method of  claim 10 , wherein directing the cooling air includes directing the cooling air though the multiple air flow paths of the at least nozzle such that the cooling air through each of the multiple air flow paths flow substantially parallel to one another. 
     
     
         13 . A gas turbine engine, comprising:
 an impingement cooled double-walled liner, including an inner liner and an outer liner, disposed around a combustion space of the turbine engine and extending from an upstream end to a downstream end; and   a plurality of nozzles extending radially inwards through the outer liner to direct cooling air towards the inner liner, each nozzle of the plurality of nozzles extending radially inwards from a first distal end to a second proximal end, wherein each nozzle of the plurality of nozzles include multiple air holes arranged in a shower head pattern at the second end.   
     
     
         14 . The gas turbine engine of  claim 13 , wherein the plurality of nozzles are arranged such that a radial gap of the second end of a nozzle to the inner liner decreases as a function of distance from the upstream end to the downstream end. 
     
     
         15 . The gas turbine engine of  claim 13 , wherein the multiple air holes are symmetrically positioned about a longitudinal axis of each nozzle. 
     
     
         16 . The gas turbine engine of  claim 15 , wherein each air hole of the multiple air holes are inclined with respect to the longitudinal axis such that the cooling air exiting each nozzle diverges. 
     
     
         17 . The gas turbine engine of  claim 16 , wherein an inclination of each air hole of the multiple air holes with respect to the longitudinal axis is substantially the same. 
     
     
         18 . The gas turbine engine of  claim 13 , wherein the second end of each nozzle includes a projection that extends towards the inner liner. 
     
     
         19 . The gas turbine engine of  claim 18 , wherein the multiple air holes are symmetrically arranged about the projection. 
     
     
         20 . The gas turbine engine of  claim 13 , wherein the second end of each nozzle is curved such that a central portion of the second end forms a proximal-most portion of the nozzle.