Convection cooling at low effusion density region of combustor panel

Abstract

A combustor for a gas turbine engine includes a combustion chamber defined between an inner shell and an outer shell. The combustor further includes a bulkhead extending between the inner shell and the outer shell. The combustor further includes a liner panel mounted to one of the inner shell and the outer shell aft of the bulkhead. The liner panel includes a first section including a first plurality of effusion holes. A first portion of the first plurality of effusion holes extends in a substantially circumferential direction. A second portion of the first plurality of effusion holes, disposed forward of the first portion, transitions from the substantially circumferential direction toward a substantially forward direction. A third portion of the first plurality of effusion holes, disposed aft of the first portion, transitions from the substantially circumferential direction to a substantially aft direction.

What is claimed is: 
     
         1 . A combustor for a gas turbine engine, the combustor comprising:
 a combustion chamber defined between an inner shell and an outer shell;   a bulkhead extending between the inner shell and the outer shell; and   a liner panel mounted to one of the inner shell and the outer shell aft of the bulkhead, the liner panel comprising a first section comprising a first plurality of effusion holes extending through the liner panel between an inner surface and an outer surface, a first portion of the first plurality of effusion holes extending in a substantially circumferential direction, a second portion of the first plurality of effusion holes, disposed forward of the first portion, transitioning from the substantially circumferential direction toward a substantially forward direction as a first axial distance from the first portion increases, a third portion of the first plurality of effusion holes, disposed aft of the first portion, transitioning from the substantially circumferential direction to a substantially aft direction as a second axial distance from the first portion increases.   
     
     
         2 . The combustor of  claim 1 , wherein the liner panel further comprises a second section comprising a second plurality of effusion holes extending through the liner panel between the inner surface and the outer surface. 
     
     
         3 . The combustor of  claim 2 , wherein the second plurality of effusion holes has a greater density of effusion holes than the first plurality of effusion holes. 
     
     
         4 . The combustor of  claim 3 , wherein each effusion hole of the second plurality of effusion holes is directed in the substantially aft direction from the outer surface to the inner surface. 
     
     
         5 . The combustor of  claim 4 , wherein effusion holes of the second portion of the first plurality of effusion holes are directed toward the bulkhead so as to direct cooling air toward an aft surface of the bulkhead. 
     
     
         6 . The combustor of  claim 5 , wherein a forward end of the liner panel is axially adjacent the aft surface of the bulkhead. 
     
     
         7 . The combustor of  claim 5 , further comprising a heat shield panel mounted to the aft surface of the bulkhead, wherein effusion holes of the second portion of the first plurality of effusion holes are configured to provide cooling air for cooling the heat shield panel. 
     
     
         8 . The combustor of  claim 4 , wherein effusion holes of the first plurality of effusion holes are oriented through the liner panel at an angle between 15 and 35 degrees relative to the inner surface of the liner panel. 
     
     
         9 . The combustor of  claim 4 , wherein the third portion of the first plurality of effusion holes comprises a plurality of effusion hole rows, each effusion hole row extending in the substantially circumferential direction along the liner panel and wherein effusion holes of each effusion hole row of the plurality of effusion hole rows, proceeding axially aft from the first portion of the first plurality of effusion holes, are directed increasingly toward the substantially aft direction and away from the substantially circumferential direction. 
     
     
         10 . The combustor of  claim 9 , wherein the plurality of effusion hole rows comprises at least four effusion hole rows. 
     
     
         11 . A method for convectively cooling a liner panel of a combustor for a gas turbine engine, the method comprising:
 providing the combustor comprising a combustion chamber defined between an inner shell and an outer shell, the combustor further comprising a bulkhead extending between the inner shell and the outer shell; and   convectively cooling the liner panel mounted to one of the inner shell and the outer shell aft of the bulkhead with a first plurality of effusion holes disposed in a first section of the liner panel, a first portion of the first plurality of effusion holes extending in a substantially circumferential direction, a second portion of the first plurality of effusion holes, disposed forward of the first portion, transitioning from the substantially circumferential direction toward a substantially forward direction as a first axial distance from the first portion increases, a third portion of the first plurality of effusion holes, disposed aft of the first portion, transitioning from the substantially circumferential direction to a substantially aft direction as a second axial distance from the first portion increases.   
     
     
         12 . The method of  claim 11 , wherein the liner panel further comprises a second section comprising a second plurality of effusion holes extending through the liner panel between the inner surface and the outer surface. 
     
     
         13 . The method of  claim 12 , wherein the second plurality of effusion holes has a greater density of effusion holes than the first plurality of effusion holes. 
     
     
         14 . The method of  claim 13 , wherein each effusion hole of the second plurality of effusion holes is directed in the substantially aft direction from the outer surface to the inner surface. 
     
     
         15 . The method of  claim 14 , further comprising directing cooling air toward an aft surface of the bulkhead with the second portion of the first plurality of effusion holes. 
     
     
         16 . The method of  claim 15 , further comprising providing a heat shield panel mounted to the aft surface of the bulkhead and cooling the heat shield by directing cooling air toward the heat shield with the second portion of the first plurality of effusion holes. 
     
     
         17 . The method of  claim 14 , wherein effusion holes of the first plurality of effusion holes are oriented through the liner panel at an angle between 15 and 35 degrees relative to the inner surface of the liner panel. 
     
     
         18 . A combustor for a gas turbine engine, the combustor comprising:
 a combustion chamber defined between an inner shell and an outer shell;   a bulkhead extending between the inner shell and the outer shell; and   a liner panel mounted to one of the inner shell and the outer shell aft of the bulkhead, the liner panel comprising a first section comprising a first plurality of effusion holes extending through the liner panel between an inner surface and an outer surface, a first portion of the first plurality of effusion holes extending in a substantially circumferential direction and a third portion of the first plurality of effusion holes, disposed aft of the first portion, transitioning from the substantially circumferential direction to a substantially aft direction as a second axial distance from the first portion increases, the third portion of the first plurality of effusion holes comprising a plurality of effusion hole rows, each effusion hole row extending in the substantially circumferential direction along the liner panel and effusion holes of each effusion hole row of the plurality of effusion hole rows, proceeding axially aft from the first portion of the first plurality of effusion holes, are directed increasingly toward the substantially aft direction and away from the substantially circumferential direction, the plurality of effusion hole rows comprising at least four effusion hole rows, the effusion holes of the first plurality of effusion holes oriented through the liner panel at an angle between 15 and 35 degrees relative to the inner surface of the liner panel.   
     
     
         19 . The combustor of  claim 18 , wherein the liner panel further comprises a second section comprising a second plurality of effusion holes extending through the liner panel between the inner surface and the outer surface, the second plurality of effusion holes having a greater density of effusion holes than the first plurality of effusion holes and each effusion hole of the second plurality of effusion holes being directed in the substantially aft direction from the outer surface to the inner surface. 
     
     
         20 . The combustor of  claim 19 , wherein a second portion of the first plurality of effusion holes, disposed forward of the first portion, transitions from the substantially circumferential direction toward a substantially forward direction as a first axial distance from the first portion increases.