Turbine airfoil with internal cooling channels

Abstract

A turbine airfoil ( 10 ) with an internal cooling system ( 12 ) having one or more bladders ( 14 ) forming near-wall cooling channels ( 16 ) is disclosed. The bladder ( 14 ) may be conformed to a shape of an inner surface ( 44 ) forming a cavity ( 18 ) within the internal cooling system ( 12 ). One or more standoff ribs ( 56 ) may extend radially inward from the inner surface ( 44 ) forming the cavity ( 18 ) to maintain the bladder ( 14 ) in position off of the inner surface ( 44 ) so that the near-wall cooling channel ( 16 ) is formed between the bladder ( 14 ) and the inner surface ( 44 ). The near-wall cooling channel ( 16 ) may be formed by inserting a bladder ( 14 ) into the cavity ( 18 ) in a first insertable position ( 22 ) and expanding the bladder ( 14 ) into a second expanded position ( 24 ). In at least one embodiment, the chamber ( 26 ) formed by the bladder ( 14 ) may be dead space that does not contain cooling fluids as a part of the cooling system ( 12 ).

1 . A turbine airfoil comprising:
 a generally elongated hollow airfoil formed from an outer wall, and having a leading edge, a trailing edge, a pressure side, a suction side, and a cooling system positioned within interior aspects of the generally elongated hollow airfoil and formed by at least one cavity;   at least one bladder positioned within the at least one cavity of the cooling system, wherein the at least one bladder forms at least one near-wall cooling channel between an outer surface of the at least one bladder and an inner surface forming the at least one cavity of the cooling system;   wherein the at least one bladder is formed from a continuous, nonlinear wall.   
     
     
         2 . The turbine airfoil of  claim 1 , wherein the at least one bladder defines an internal chamber that is a dead space. 
     
     
         3 . The turbine airfoil of  claim 1 , further comprising at least one standoff rib extending from the inner surface forming the at least one cavity of the cooling system and into contact with the at least one bladder. 
     
     
         4 . The turbine airfoil of  claim 3 , wherein a first section of the at least one bladder laterally adjacent to a portion of the at least one bladder in contact with a tip of the at least one standoff rib is positioned closer to the inner surface forming the at least one cavity of the cooling system than the tip of the at least one standoff rib. 
     
     
         5 . The turbine airfoil of  claim 3 , further comprising a second section of the at least one bladder on an opposite side of the at least one standoff rib from the first section, wherein the second section of the at least one bladder laterally adjacent to a portion of the at least one bladder in contact with a tip of the at least one standoff rib is positioned closer to the inner surface forming the at least one cavity of the cooling system than the tip of the at least one standoff rib. 
     
     
         6 . The turbine airfoil of  claim 3 , wherein the at least one standoff rib extending from the inner surface forming the at least one cavity of the cooling system and into contact with the at least one bladder. 
     
     
         7 . The turbine airfoil of  claim 6 , wherein the at least one bladder between two adjacent standoff ribs of a first standoff rib toward the inner surface forming the at least one cavity of the cooling system to an outermost point and is curved away from the inner surface forming the at least one cavity of the cooling system and from the outermost point to a tip of a second standoff rib. 
     
     
         8 . The turbine airfoil of  claim 7 , wherein the at least one bladder extending between each of the plurality of standoff ribs is curved from a tip of a first standoff rib toward the inner surface forming the at least one cavity of the cooling system to an outermost point and is curved away from the inner surface forming the at least one cavity of the cooling system and from the outermost point to a tip of a second standoff rib. 
     
     
         9 . The turbine airfoil of  claim 6 , wherein the plurality of standoff ribs are a plurality of serpentine shaped ribs extending spanwise and offset chordwise from each other. 
     
     
         10 . The turbine airfoil of  claim 6 , wherein the plurality of standoff ribs are positioned nonparallel and nonorthogonal with a spanwise extending direction and are formed into chordwise extending rows. 
     
     
         11 . The turbine airfoil of  claim 1 , wherein the at least one bladder is formed from a material that is different from a material forming the outer wall of the generally elongated hollow airfoil. 
     
     
         12 . The turbine airfoil of  claim 11 , wherein the at least one bladder is formed from a material having greater plasticity than the material forming the outer wall of the generally elongated hollow airfoil. 
     
     
         13 . The turbine airfoil of  claim 1 , wherein the at least one bladder may be formed from a first section having a first thickness and a second section having a second thickness that is greater the first section. 
     
     
         14 . The turbine airfoil of  claim 1 , wherein the at least one bladder may be formed from a first section and a second section, whereby the first section is formed from a material having a tapered thickness.