Turbine airfoil cooling system with near wall pin fin cooling chambers

Abstract

A cooling system for a turbine airfoil of a turbine engine having a suction side near wall cooling chamber extending from the leading edge to the trailing edge. The suction side near wall cooling chamber may include a plurality of pin fins for increasing the cooling effectiveness of the suction side near wall cooling chamber. The pin fins may be formed in two or more regions having varying sizes and quantities per unit area to accommodate different cooling requirements across the airfoil. In one embodiment, cooling fluids may flow in a counterflow manner through the suction side near wall cooling chamber relative to a pressure side near wall cooling chamber. In another embodiment, the cooling fluids may flow from the leading edge through the suction side near wall cooling chamber and be exhausted through slots in the trailing edge.

1 . A turbine airfoil, comprising:
 a generally elongated, hollow airfoil having a leading edge, a trailing edge, a tip section at a first end, a root coupled to the airfoil at an end generally opposite the first end for supporting the airfoil and for coupling the airfoil to a disc, and a cooling system formed from at least one cavity in the elongated, hollow airfoil;   an outer wall forming the generally elongated airfoil;   an inner wall positioned in close proximity to the outer wall forming a pressure side near wall cooling chamber proximate to a pressure side of the generally elongated, hollow airfoil and forming a suction side near wall cooling chamber proximate to a suction side of the generally elongated, hollow airfoil;   a leading edge cooling chamber positioned proximate to the leading edge of the generally elongated, hollow airfoil and extending generally spanwise through the generally elongated, hollow airfoil;   a trailing edge cooling chamber positioned proximate to the trailing edge of the generally elongated, hollow airfoil and extending generally spanwise through the generally elongated, hollow airfoil;   wherein the pressure side near wall cooling chamber extends from the leading edge cooling chamber to the trailing edge cooling chamber and includes a plurality of pin fins extending from the outerwall to the inner wall;   wherein the suction side near wall cooling chamber extends from the leading edge cooling chamber to the trailing edge cooling chamber and includes a plurality of pin fins extending from the outerwall to the inner wall; and   wherein the pressure side near wall cooling chamber has an inlet providing cooling fluids from proximate to the leading edge such that cooling fluids flow in a direction from the leading edge toward the trailing edge and the suction side near wall cooling chamber has an inlet proximate to the trailing edge cooling chamber from the pressure side near wall cooling chamber such that cooling fluids flow in a direction from the trailing edge toward the leading edge establishing a counterflow, wherein the pressure side and suction side near wall cooling chambers are separated by a rib at the leading edge.   
     
     
         2 . The turbine airfoil of  claim 1 , wherein the plurality of pin fins in the pressure side near wall cooling chamber are formed from a first region having pin fins with first cross-sectional area with a shape and a second region having pin fins with a second cross-sectional area with the same shape that is greater than the first cross-sectional area. 
     
     
         3 . The turbine airfoil of  claim 1 , wherein the plurality of pin fins in the pressure side near wall cooling chamber are formed from a first region in a first quantity per unit area and a second region having pin fins in a second quantity per unit area that is greater than the first quantity per unit area. 
     
     
         4 . The turbine airfoil of  claim 1 , wherein the plurality of pin fins in the pressure side near wall cooling chamber are aligned in rows of pin fins extending generally spanwise. 
     
     
         5 . The turbine airfoil of  claim 4 , further comprising trip strips extending between the pin fins. 
     
     
         6 . The turbine airfoil of  claim 1 , wherein the plurality of pin fins in the pressure side near wall cooling chamber are aligned in rows of pin fins extending at an acute angle between a chordwise and spanwise directions. 
     
     
         7 . The turbine airfoil of  claim 6 , further comprising trip strips extending between the pin fins. 
     
     
         8 . The turbine airfoil of  claim 1 , wherein the plurality of pin fins in the suction side near wall cooling chamber are formed from a first region having pin fins with a first cross-sectional area with a shape and a second region having pin fins with a second cross-sectional area with the same shape that is greater than the first cross-sectional area. 
     
     
         9 . The turbine airfoil of  claim 1 , wherein the plurality of pin fins in the suction side near wall cooling chamber are formed from a first region in a first quantity per unit area and a second region having pin fins in a second quantity per unit area that is greater than the first quantity per unit area. 
     
     
         10 . The turbine airfoil of  claim 1 , wherein the plurality of pin fins in the suction side near wall cooling chamber are aligned in rows of pin fins extending generally spanwise. 
     
     
         11 . The turbine airfoil of  claim 10 , further comprising trip strips extending between the pin fins. 
     
     
         12 . The turbine airfoil of  claim 1 , wherein the plurality of pin fins in the suction side near wall cooling chamber are aligned in rows of pin fins extending at an acute angle between a chordwise and spanwise directions. 
     
     
         13 . The turbine airfoil of  claim 12 , further comprising trip strips extending between the pin fins. 
     
     
         14 . The turbine airfoil of  claim 1 , further comprising pin fins positioned in the trailing edge cooling chamber. 
     
     
         15 . The turbine airfoil of  claim 1 , further comprising at least one refresh hole in the inner wall separating the leading edge cooling chamber from the trailing edge cooling chamber. 
     
     
         16 . The turbine airfoil of  claim 1 , further comprising a central cooling fluid supply channel positioned between the pressure side and suction side near wall cooling chambers, formed by a second inner wall and extending from the leading edge cooling chamber to the trailing edge cooling chamber. 
     
     
         17 . (canceled) 
     
     
         18 . A turbine airfoil, comprising:
 a generally elongated, hollow airfoil having a leading edge, a trailing edge, a tip section at a first end, a root coupled to the airfoil at an end generally opposite the first end for supporting the airfoil and for coupling the airfoil to a disc, and a cooling system formed from at least one cavity in the elongated, hollow airfoil;   an outer wall forming the generally elongated airfoil;   an inner wall positioned in close proximity to the outer wall forming a suction side near wall cooling chamber proximate to a suction side of the generally elongated, hollow airfoil and a pressure side cooling chamber proximate to a pressure side of the generally elongated, hollow airfoil, wherein the pressure side cooling chamber is adjacent to the suction side near wall cooling chamber;   a leading edge cooling chamber positioned proximate to the leading edge of the generally elongated, hollow airfoil and extending generally spanwise through the generally elongated, hollow airfoil;   a trailing edge cooling slots positioned proximate to the trailing edge of the generally elongated, hollow airfoil;   wherein the suction side near wall cooling chamber extends from the leading edge cooling chamber to the trailing edge cooling slots and includes a plurality of pin fins extending from the outerwall to the inner wall;   wherein the pressure side near wall cooling chamber extends from the leading edge cooling chamber to the trailing edge cooling chamber and includes a plurality of pin fins extending from the outerwall to the inner wall; and   wherein the pressure side near wall cooling chamber has an inlet providing cooling fluids from proximate to the leading edge such that cooling fluids flow in a direction from the leading edge toward the trailing edge and the suction side near wall cooling chamber has an inlet proximate to the trailing edge cooling chamber from the pressure side near wall cooling chamber such that cooling fluids flow in a direction from the trailing edge toward the leading edge establishing a counterflow, wherein the pressure side and suction side near wall cooling chambers are separated by a rib at the leading edge.   
     
     
         19 . The turbine airfoil of  claim 18 , wherein the plurality of pin fins in the suction side near wall cooling chamber are formed from a first region having fin pins with first cross-sectional area with a shape and a second region having pin fins with a second cross-sectional area with the same shape that is greater than the first cross-sectional area and wherein the plurality of pin fins in the second region of the suction side near wall cooling chamber are aligned in rows of pin fins extending generally spanwise and wherein the plurality of pin fins in the first region of the suction side near wall cooling chamber are aligned in rows of pin fins extending at an acute angle between a chordwise and spanwise directions. 
     
     
         20 . The turbine airfoil of  claim 18 , wherein the plurality of pin fins in the pressure side cooling chamber are formed from a first region having fin pins with first cross-sectional area and a second region having pin fins with a second cross-sectional area that is greater than the first cross-sectional area.