Variable vane segment

Abstract

A variable vane pack includes an inner platform, an outer platform, radially outward of the inner platform, a plurality of vanes connecting the inner platform to the outer platform, wherein the outer platform comprises a platform body and an impingement plate, the impingement plate having a radially inward impingement plate, a radially outward pressure distribution plate, and an impingement plenum defined between the radially inward impingement plate and the radially outward pressure distribution plate.

1 . A method for cooling an engine component comprising:
 providing a cooling air feed to said engine components;   passing said cooling air through a pressure distribution plate into an impingement plenum, thereby providing an even distribution of air pressure to said impingement plenum;   feeding said cooling air through impingement openings in an impingement plate, thereby impinging cooling air on a radially outward platform of said engine component and cooling said radially outward platform.   
     
     
         2 . The method of  claim 1 , wherein passing said cooling air through a pressure distribution plate into an impingement plenum comprises passing cooling air through a plurality of slots in the distribution plate. 
     
     
         3 . The method of  claim 2 , wherein each of the slots overlaps at least one adjacent slot along an axis defined by the curvature of the engine component. 
     
     
         4 . The method of  claim 2 , wherein each of the slots circumferentially overlaps at least one adjacent slot. 
     
     
         5 . The method of  claim 1 , wherein cooling air exits said impingement plenum at least one of a joint between said engine component and an adjacent engine component, and a plurality of openings in said radially outward platform. 
     
     
         6 . The method of  claim 1 , wherein feeding said cooling air through a plurality of impingement openings in an impingement plate, comprises providing a plurality of impingement airflows to said radially outward platform from said plurality of impingement openings and wherein each of said plurality of impingement airflows has an approximately even pressure, thereby achieving an even cooling airflow pressure gradient across said radially outward platform. 
     
     
         7 . The method of claim  11 , further comprising providing cooling air to each vane in said engine component through at least one outer cooling air feed and wherein cooling air provided to said outer cooling air feed and said pressure distribution plate are provided by the same air feed. 
     
     
         8 . A gas turbine engine comprising:
 a compressor section;   a combustor section in fluid fluidly connected to the compressor section via a primary flowpath;   a turbine section fluidly connected to the combustor section by the primary flowpath;   a plurality of vane packs disposed circumferentially in said primary flowpath such that a vane stage is formed in said flowpath; and   wherein each of said vane packs comprises:
 an inner platform; 
 an outer platform, radially outward of said inner platform; 
 a plurality of vanes connecting said inner platform to said outer platform; 
 wherein the outer platform comprises a platform body and an impingement plate, the impingement plate having a radially inward impingement plate, a radially outward pressure distribution plate, and an impingement plenum defined between said radially inward impingement plate and said radially outward pressure distribution plate. 
   
     
     
         9 . The gas turbine engine of  claim 8 , wherein each radially outward pressure distribution plate comprises a plurality of slots, each of said slots axially and circumferentially overlapping at least one other of said slots, and wherein each of said slots provides a cooling air flowpath from an outer cooling plenum to said impingement plenum. 
     
     
         10 . The gas turbine engine of  claim 8 , wherein said radially inward impingement plate comprises a plurality of impingement openings operable to allow cooling air to move from said impingement plenum to said outer platform.