Turbine airfoil with integral chordal support ribs

Abstract

A turbine airfoil including a structural support system formed from chordal ribs within an internal cooling system in the airfoil. The chordal ribs forming the structural support system may be positioned in a cooling fluid supply channel in the hollow airfoil that is positioned proximate to a trailing edge cooling channel. The trailing edge cooling channel may include a plurality of pin fins forming a pin fin bank extending between inner surfaces of the pressure side wall and suction side wall. The chordal ribs may protrude from an inner surface of the outer wall of the hollow airfoil and extend in a general chordwise direction from a mid-chord region of the hollow airfoil to the trailing edge and into the pin fin bank. The structural support system reduces stresses proximate to the pin fins in the pin fin bank closest to the mid-chord region of the airfoil.

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 wall, a suction side wall positioned generally opposite from the pressure side wall; and    a cooling system in the hollow airfoil, comprising: 
 at least one trailing edge cooling channel positioned immediately adjacent to the trailing edge of the hollow airfoil;  
 at least one cooling fluid supply channel in the hollow airfoil positioned proximate to the trailing edge cooling channel and extending between an inner surface of the pressure side wall and an inner surface of the suction side wall;  
 a plurality of pin fins forming a pin fin bank extending between an inner surface of the pressure side wall and an inner surface of the suction side wall and positioned in the trailing edge cooling channel; and  
 at least one chordal rib protruding from an inner surface of the outer wall of the hollow airfoil and extending in a general chordwise direction from a mid-chord region of the hollow airfoil toward the trailing edge and into the pin fin bank.  
   
     
     
         2 . The turbine airfoil of  claim 1 , wherein the at least one chordal rib comprises a plurality of chordal ribs protruding from an inner surface of the outer wall of the hollow airfoil and extending in a general chordwise direction from a mid-chord region of the hollow airfoil toward the trailing edge and into the pin fin bank.  
     
     
         3 . The turbine airfoil of  claim 2 , wherein the plurality of chordal ribs are positioned generally parallel to each other.  
     
     
         4 . The turbine airfoil of  claim 2 , wherein the plurality of chordal ribs extend from an inner surface of the suction side wall to an inner surface of the pressure side wall in the pin fin bank.  
     
     
         5 . The turbine airfoil of  claim 1 , further comprising a support rib extending between an inner surface of the pressure side wall and an inner surface of the suction side wall in the mid-chord region of the hollow airfoil and extending in a general spanwise direction to form a wall defining the at least one cooling fluid supply channel.  
     
     
         6 . The turbine airfoil of  claim 5 , wherein at least one chordal rib extends from the support rib to the trailing edge of the hollow airfoil.  
     
     
         7 . The turbine airfoil of  claim 1 , wherein the at least one chordal rib protruding from the outer wall of the hollow airfoil protrudes from the suction side wall.  
     
     
         8 . The turbine airfoil of  claim 1 , wherein at least one chordal rib extends from an inner surface of the suction side wall to an inner surface of the pressure side wall in the pin fin bank.  
     
     
         9 . The turbine airfoil of  claim 1 , wherein the at least one chordal rib protruding from an inner surface of the outer wall of the hollow airfoil comprises a plurality of protrusions extending from the at least one chordal rib within the pin fin bank.  
     
     
         10 . The turbine airfoil of  claim 1 , wherein the at least one chordal rib protrudes from the inner surface of the outer wall into the at least one cooling fluid supply channel a distance between about two times and four times a thickness of the outer wall.  
     
     
         11 . The turbine airfoil of  claim 1 , wherein plurality of pin fins forming the pin fin bank form a plurality of rows of pin fins that extend generally in a spanwise direction.  
     
     
         12 . The turbine airfoil of  claim 11 , wherein the pin fins forming the rows extending in a generally spanwise direction are offset in a spanwise direction relative to pin fins in adjacent rows of pin fins.  
     
     
         13 . The turbine airfoil of  claim 1 , further comprising a plurality of crossover ribs extending between the inner surface of the pressure side wall to the inner surface of the suction side wall and positioned in the cooling fluid supply channel in close proximity to the pin fin bank.  
     
     
         14 . 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 wall, a suction side wall positioned generally opposite from the pressure side wall; and    a cooling system in the hollow airfoil, comprising: 
 at least one trailing edge cooling channel positioned immediately adjacent to the trailing edge of the hollow airfoil;  
 at least one cooling fluid supply channel in the hollow airfoil positioned proximate to the trailing edge cooling channel and extending between an inner surface of the pressure side wall and an inner surface of the suction side wall;  
 a support rib extending between an inner surface of the pressure side wall and an inner surface of the suction side wall in a mid-chord region of the hollow airfoil and extending in a general spanwise direction to form a wall defining the at least one fluid supply channel;  
 a plurality of pin fins forming a pin fin bank extending between an inner surface of the pressure side wall to and an inner surface of the suction side wall and positioned in the trailing edge cooling channel;  
 a plurality of chordal ribs protruding from an inner surface of the suction side wall of the hollow airfoil and extending in a general chordwise direction from the support rib in the mid-chord region of the hollow airfoil to the trailing edge and into the pin fin bank; and  
 a plurality of crossover ribs extending between the inner surface of the pressure side wall to the inner surface of the suction side wall and positioned in the cooling fluid supply channel in close proximity to the pin fin bank.  
   
     
     
         15 . The turbine airfoil of  claim 14 , wherein the plurality of chordal ribs extend from an inner surface of the suction side wall to an inner surface of the pressure side wall in the pin fin bank.  
     
     
         16 . The turbine airfoil of  claim 14 , wherein the chordal ribs protruding from an inner surface of the outer wall of the hollow airfoil comprises a plurality of protrusions extending from ID sides of the chordal rib and from OD sides of the chordal ribs within the pin fin bank.  
     
     
         17 . The turbine airfoil of  claim 16 , wherein the protrusions are aligned with rows of pin fins that extend in a spanwise direction forming the pin fin bank.  
     
     
         18 . The turbine airfoil of  claim 14 , wherein plurality of pin fins forming the pin fin bank form a plurality of rows of pin fins that extend generally in a spanwise direction and wherein the pin fins forming the rows extending in a generally spanwise direction are offset in a spanwise direction relative to pin fins in adjacent rows of pin fins.  
     
     
         19 . The turbine airfoil of  claim 14 , wherein the at least one chordal rib protrudes from the inner surface of the suction side wall into the at least one cooling fluid supply channel a distance between about two times and four times a thickness of the suction side wall.  
     
     
         20 . 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 wall, a suction side wall positioned generally opposite from the pressure side wall; and    a cooling system in the hollow airfoil, comprising: 
 at least one trailing edge cooling channel positioned immediately adjacent to the trailing edge of the hollow airfoil;  
 at least one cooling fluid supply channel in the hollow airfoil positioned proximate to the trailing edge cooling channel and extending between an inner surface of the pressure side wall and an inner surface of the suction side wall;  
 a support rib extending between an inner surface of the pressure side wall and an inner surface of the suction side wall in a mid-chord region of the hollow airfoil and extending in a general spanwise direction to form a wall defining the at least one fluid supply channel;  
 a plurality of pin fins forming a pin fin bank extending between an inner surface of the pressure side wall to and an inner surface of the suction side wall and positioned in the trailing edge cooling channel; and  
 a plurality of crossover ribs extending between the inner surface of the pressure side wall to the inner surface of the suction side wall and positioned in the cooling fluid supply channel in close proximity to the pin fin bank.