Ceramic casting core having an integral vane internal core and shroud backside shell for vane segment casting

Abstract

A cast ceramic core ( 110 ), including: an airfoil portion ( 116 ) shaped to define an inner surface ( 56 ) of an airfoil ( 52 ) of a vane segment ( 50 ); and a shell portion ( 122 ) having a backside-shaping surface ( 120 ) shaped to define a backside surface ( 68 ) of a shroud ( 62 ) of the vane segment. The backside-shaping surface has a higher elevation ( 132 ) and a lower elevation ( 134 ). The higher elevation is set apart from a nearest point ( 138 ) on the airfoil portion by the lower elevation. The airfoil portion and the shell portion are cast as a monolithic body during a single casting pour.

The invention claimed is: 
     
         1 . A cast ceramic core, comprising:
 an airfoil portion shaped to define an inner surface of an airfoil of a vane segment; and   a shell portion comprising a backside-shaping surface shaped to define a backside surface of a shroud of the vane segment, the backside-shaping surface comprising a higher elevation and a lower elevation, the higher elevation being set apart from a nearest point on the airfoil portion by the lower elevation,   wherein the airfoil portion and the shell portion are cast as a monolithic body during a single casting pour.   
     
     
         2 . The cast ceramic core of  claim 1 , wherein the shell portion defines the backside surface of an outer shroud of the vane segment, and wherein the cast ceramic core further comprises an opposing shell portion comprising an opposing backside-shaping surface shaped to define a backside surface of an inner shroud of the vane segment, the opposing backside-shaping surface comprising the higher elevation and the lower elevation, the higher elevation being set apart from a respective nearest point of the airfoil portion by the lower elevation. 
     
     
         3 . A cast ceramic core, comprising an airfoil portion shaped to define an inner surface of an airfoil of a vane segment and a shell portion shaped to define a backside surface of a shroud of the vane segment, wherein the airfoil portion and the shell portion are formed as a single casting. 
     
     
         4 . The cast ceramic core of  claim 3 , wherein the shell portion further comprises core shell features shaped to define heat transfer features on the backside surface of a vane segment shroud. 
     
     
         5 . The cast ceramic core of  claim 4 , wherein the airfoil portion comprises core airfoil features shaped to define heat transfer features on the inner surface of a vane segment airfoil. 
     
     
         6 . The cast ceramic core of  claim 4 , wherein the core shell features form a higher elevation and a lower elevation in the shell portion, the higher elevation being set apart from a nearest point on the airfoil portion. 
     
     
         7 . The cast ceramic core of  claim 3 , wherein the shell portion defines the backside surface of an outer shroud of the vane segment, and wherein the cast ceramic core further comprises an opposing shell portion shaped to define a backside surface of an inner shroud of the vane segment. 
     
     
         8 . The cast ceramic core of  claim 7 , wherein the shell portion further comprises core shell features shaped to define heat transfer features on the backside surface of the outer shroud, wherein the opposing shell portion further comprises core shell features shaped to define heat transfer features on the backside surface of the inner shroud. 
     
     
         9 . The cast ceramic core of  claim 8 , wherein the core shell features on at least one of the shell portions form a higher elevation and a lower elevation in the at least one shell portion, the higher elevation being set apart from a nearest point on the airfoil portion. 
     
     
         10 . The cast ceramic core of  claim 8 , wherein the core shell features on both shell portions comprises a plurality of dimples. 
     
     
         11 . A cast ceramic core, comprising:
 a monolithic body comprising:
 an airfoil portion shaped to define an inner surface of an airfoil of a vane segment; 
 an outer shell portion shaped to define a backside surface of an outer shroud of the vane segment; and 
 an inner shell portion comprising a core backside-shaping surface shaped to define a backside surface of an inner shroud of the vane segment. 
   
     
     
         12 . The cast ceramic core of  claim 11 , wherein at least one of the core shell portions is further shaped to define a heat transfer feature on a respective backside surface of the vane segment. 
     
     
         13 . The cast ceramic core of  claim 12 , wherein the further shaping forms a higher elevation and a lower elevation in the at least one shell portion, the higher elevation being set apart from a nearest point on the airfoil portion. 
     
     
         14 . The cast ceramic core of  claim 12 , wherein the further shaping forms a plurality of dimples on the respective backside surface. 
     
     
         15 . The cast ceramic core of  claim 12 , wherein both backside-shaping surfaces are further shaped to define heat transfer features on respective backside surfaces of the vane segment, the further shaping forming a higher elevation and a lower elevation in each backside-shaping surface, the higher elevations being set apart from respective nearest point of the airfoil portion. 
     
     
         16 . The cast ceramic core of  claim 15 , wherein the further shaping forms a plurality of dimples.