Gas turbine engine sealing arrangement

Abstract

A sealing arrangement for a gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, a groove that extends between an upstream rail and a downstream rail, a complementary static structure spaced from the groove, and a seal positioned within the groove and configured to seal a clearance between at least one of the upstream rail and the downstream rail and the complementary static structure.

What is claimed is: 
     
         1 . A static frame for a gas turbine engine, comprising:
 an annular platform, the platform having a first platform surface that faces radially toward a core flow path and includes a plurality of airfoils extending therefrom, and a second platform surface that faces radially away from the core flow path;   a static structure disposed radially adjacent to the second platform surface, the static structure including a third platform surface that radially faces the second platform surface, wherein said static structure is a mid-turbine frame arranged between a first turbine and a second turbine; and   a fluid seal between the second platform surface and the third platform surface, the fluid seal comprising:
 a first annular rail extending radially from the second platform surface toward the third platform surface by a first distance; 
 a second annular rail that is axially spaced from the first annular rail, the second annular rail extending radially from the second platform surface towards the third platform surface by a second distance that is less than the first distance; 
 an annular groove on the second platform surface defined between the first annular rail and the second annular rail so that the annular groove is J-shaped; and 
 an annular seal extending from the third platform surface into the annular groove to form a sealing relationship between the annular seal and the second annular rail. 
   
     
     
         2 . The static frame as recited in  claim 1 , wherein said groove and said seal are arranged at an inner diameter portion of the static frame. 
     
     
         3 . The static frame as recited in  claim 2 , wherein said seal is a piston seal that applies a springing force against said static structure. 
     
     
         4 . The static frame as recited in  claim 3 , wherein at least one of said first annular rail and said second annular rail includes a plurality of circumferentially distributed relief slots. 
     
     
         5 . The static frame as recited in  claim 4 , wherein a first clearance extends between said first annular rail and said static structure, and a second, larger clearance extends between said second annular rail and said static structure. 
     
     
         6 . The static frame as recited in  claim 1 , wherein said groove and said seal are arranged at an aft portion of the static frame. 
     
     
         7 . The static frame as recited in  claim 6 , wherein said seal is a piston seal that applies a springing force against said static structure. 
     
     
         8 . The static frame as recited in  claim 7 , wherein at least one of said first annular rail and said second annular rail includes a plurality of circumferentially distributed relief slots, a first clearance extends between said first annular rail and said static structure, and a second, larger clearance extends between said second annular rail and said static structure. 
     
     
         9 . A static structure for a gas turbine engine, comprising:
 an airfoil that extends between an inner platform and an outer platform;   a sealing arrangement that includes a groove formed in at least one of said inner platform and said outer platform and a seal received within said groove, wherein said groove extends between an upstream rail and a downstream rail, and wherein said upstream rail extends to a first distance from an engine centerline longitudinal axis and said downstream rail extends to a second, different distance from said engine centerline longitudinal axis; and   wherein said static structure is a mid-turbine frame arranged between a first turbine and a second turbine.   
     
     
         10 . The static structure as recited in  claim 9 , wherein said seal is positioned at an aft portion of said static structure. 
     
     
         11 . The static structure as recited in  claim 10 , wherein said seal is a piston seal that applies a springing force against a casing spaced from said inner platform or said outer platform. 
     
     
         12 . The static structure as recited in  claim 10 , wherein at least one of said upstream rail and said downstream rail includes a plurality of circumferentially distributed relief slots. 
     
     
         13 . The static structure as recited in  claim 9 , wherein said groove is formed in a non-gas path surface of said inner platform. 
     
     
         14 . The static structure as recited in  claim 13 , wherein at least one of said upstream rail and said downstream rail includes a plurality of circumferentially distributed relief slots. 
     
     
         15 . The static structure as recited in  claim 13 , wherein said seal extends between said groove and an inner casing radially inward of said seal. 
     
     
         16 . A gas turbine engine, comprising:
 a compressor section;   a turbine section including a first turbine and a second turbine; and   a static structure associated with said turbine section, wherein said static structure includes an airfoil that extends between an outer platform and an inner platform, said static structure being a mid-turbine frame arranged between said first and second turbines;   a sealing arrangement that is part of at least one of said outer platform and said inner platform, said sealing arrangement including a groove that extends between an upstream rail and a downstream rail and a seal received within said groove, and wherein said upstream rail extends to a first distance from an engine centerline longitudinal axis and said downstream rail extends to a second, different distance from said engine centerline longitudinal axis.   
     
     
         17 . The gas turbine engine as recited in  claim 16 , wherein said groove and said seal are arranged at an inner diameter portion of the static frame. 
     
     
         18 . The gas turbine engine as recited in  claim 17 , wherein said seal is a piston seal that applies a springing force against said static structure, at least one of said upstream rail and said downstream rail is tapered, each of said upstream rail and said downstream rail includes a plurality of relief slots, with at least some relief slots of said plurality of relief slots of said upstream rail circumferentially aligned with at least some relief slots of said plurality of relief slots of said downstream rail. 
     
     
         19 . The gas turbine engine as recited in  claim 16 , wherein said groove and said seal are arranged at an aft portion of the static frame. 
     
     
         20 . The gas turbine engine as recited in  claim 19 , wherein said seal is a piston seal that applies a springing force against said static structure, at least one of said upstream rail and said downstream rail is tapered, each of said upstream rail and said downstream rail includes a plurality of relief slots, with at least some relief slots of said plurality of relief slots of said upstream rail circumferentially aligned with at least some relief slots of said plurality of relief slots of said downstream rail.