Contoured Stator Shroud

Abstract

A contoured stator shroud has a stator chord overhang having a surface which varies in elevation forming a plurality of surface contours, wherein the contours reduce clearance between adjacent vanes during off design performance positioning of the vanes.

What is claimed is: 
     
         1 . A contoured stator shroud vane assembly in a gas turbine engine having an inlet end, an outlet end and a plurality of propulsor components, comprising:
 a stator shroud having a generally circular cross-section;   said shroud having a forward end, an aft end and at least one surface extending between said first end and said second end;   said shroud having a plurality of pivots disposed circumferentially about said shroud to support a trunnion of a vane;   said at least one surface of varying elevation adjacent to said plurality of pivots, and extending in a circumferential direction.   
     
     
         2 . The contoured stator shroud vane assembly of  claim 1 , said surface of varying elevation of at least one surface disposed adjacent an edge of said vane. 
     
     
         3 . The contoured stator shroud vane assembly of  claim 2 , said surface of varying elevation being curved to approximate the curvature defined by rotation of said edge of said vane. 
     
     
         4 . The contoured stator shroud vane assembly of  claim 3 , wherein said vane overhang and said surface of varying elevation inhibit leakage when said vane pivots. 
     
     
         5 . The contoured stator shroud vane assembly of  claim 1 , said plurality of pivots each receiving buttons of a plurality of vanes. 
     
     
         6 . The contoured stator shroud vane assembly of  claim 1 , said axes of curvature of said surface of varying elevation being generally parallel to an engine axis. 
     
     
         7 . A contoured stator shroud, comprising:
 a forward end, an aft end and at least one surface extending between said forward end and said aft end;   said at least one surface being tapered from said forward end to said aft end;   a plurality of areas of varying elevation disposed about said at least one surface, said plurality of areas each having a peak and a valley;   a plurality of pivot apertures spaced about a forward end of said at least one surface.   
     
     
         8 . The contoured stator shroud of  claim 7 , said plurality of areas of varying elevation being curved from a first elevation to a second elevation in a circumferential direction. 
     
     
         9 . The contoured stator shroud of  claim 7 , said plurality of varying elevation being linear from a first elevation to a second elevation in a circumferential direction. 
     
     
         10 . The contoured stator shroud of  claim 7 , said shroud changing elevation in an axial direction. 
     
     
         11 . The contoured stator shroud of  claim 10 , said changing elevation being curved. 
     
     
         12 . The contoured stator shroud of  claim 10 , said changing elevation being linear. 
     
     
         13 . The contoured stator shroud of  claim 7  further comprising a vane having a lowermost edge. 
     
     
         14 . The contoured stator shroud of  claim 13 , said lowermost edge engaging said plurality of areas of varying elevation during pivoting movement of said vane. 
     
     
         15 . The contoured stator shroud vane assembly of  claim 7 , said plurality of areas of varying elevation additionally being curved to approximate the curvature defined by rotation of a lower edge of a vane. 
     
     
         16 . A contoured stator shroud, comprising:
 a forward end and an aft end, at least one surface extending between said forward end and said second end;   said at least one surface having a scalloped chord overhang area, said scalloped area extending in a circumferential direction;   a plurality of vane mounting locations disposed circumferentially between said forward end and said aft end.   
     
     
         17 . The contoured stator shroud of  claim 16 , said scalloped chord overhang area being curved from a lower elevation of said stator shroud to an upper elevation of said stator shroud. 
     
     
         18 . The contoured stator shroud of  claim 16  further comprising a plurality of vanes operably connected to said plurality of vane mounting locations. 
     
     
         19 . The contoured stator shroud of  claim 18 , said plurality of vanes each having an edge extending between a leading edge and a trailing edge. 
     
     
         20 . The contoured stator shroud of  claim 19 , said edge engaging a scalloped chord overhang area during pivoting movement of said vane.