Turbine airfoil cooling system with enhanced tip corner cooling channel

Abstract

A cooling system for a turbine airfoil of a turbine engine having a serpentine cooling channel with a portion positioned proximate to an intersection between a trailing edge and the tip section of the airfoil. The serpentine cooling channel may extend generally spanwise between a root and the tip section of the airfoil and may include a portion extending generally chordwise. The chordwise portion of the serpentine cooling channel may extend between the spanwise portion of the serpentine cooling channel and a trailing edge of the airfoil. The chordwise portion may include an exhaust orifice in the trailing edge and at a trailing edge turn in the serpentine cooling channel. The trailing edge turn provides a more efficient cooling channel for the cooling system which reduces the local temperature of the airfoil at the tip flag.

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 to 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;   the cooling system comprising a serpentine cooling channel positioned in a mid-chord region of the generally elongated airfoil and being formed from a first leg, a second leg, a third leg, a fourth leg, and a fifth leg;   wherein the first, fourth and fifth legs are generally aligned with each other and extend in a generally spanwise direction;   wherein the second and third legs are generally aligned with each other and extend in a generally chordwise direction proximate to an intersection between the trailing edge and the tip section of the generally elongated, hollow airfoil; and   a trailing edge turn between the second and third legs including a trailing edge exhaust orifice in the trailing edge.   
     
     
         2 . The turbine airfoil of  claim 1 , further comprising a rib positioned in the trailing edge turn between the second and third legs. 
     
     
         3 . The turbine airfoil of  claim 2 , wherein the rib extends generally chordwise and contacts the trailing edge. 
     
     
         4 . The turbine airfoil of  claim 1 , further comprising a trailing edge cooling channel in contact with the trailing edge and extending from the root to the second leg of the serpentine cooling channel. 
     
     
         5 . The turbine airfoil of  claim 4 , further comprising at least one trailing edge exhaust orifice in fluid communication with the trailing edge cooling channel. 
     
     
         6 . The turbine airfoil of  claim 5 , further comprising at least one impingement rib in the trailing edge cooling channel that extends in a spanwise direction, wherein the impingement rib includes a plurality of impingement orifices. 
     
     
         7 . The turbine airfoil of  claim 1 , further comprising at least one leading edge cooling channel positioned proximate to the leading edge. 
     
     
         8 . The turbine airfoil of  claim 7 , further comprising at least one leading edge supply channel in fluid communication with the at least one leading edge cooling channel. 
     
     
         9 . The turbine airfoil of  claim 8 , further comprising a plurality of impingement orifices in a rib separating the at least one leading edge supply channel from the at least one leading edge cooling channel. 
     
     
         10 . The turbine airfoil of  claim 1 , further comprising at least one trip strip in at least one of the legs of the serpentine cooling channel. 
     
     
         11 . The turbine airfoil of  claim 10 , wherein the at least one trip strip protrudes from an outer wall forming a pressure side of the generally elongated airfoil. 
     
     
         12 . The turbine airfoil of  claim 11 , wherein the at least one trip strip comprises a plurality of trip strips protruding from the outer walls forming the pressure side and a suction side of the generally elongated airfoil. 
     
     
         13 . 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 to 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;   the cooling system comprising a serpentine cooling channel positioned in a mid-chord region of the generally elongated airfoil and being formed from a first leg, a second leg, a third leg, a fourth leg, and a fifth leg;   wherein the first, fourth and fifth legs are generally aligned with each other and extend in a generally spanwise direction;   wherein the second and third legs are generally aligned with each other and extend in a generally chordwise direction between a trailing edge cooling channel and an intersection between the trailing edge and the tip section of the generally elongated, hollow airfoil;   a trailing edge trailing edge turn between the second and third legs including a trailing edge exhaust orifice in the trailing edge;   the trailing edge cooling channel in contact with the trailing edge and extending from the root to the second leg of the serpentine cooling channel and the trailing edge trailing edge turn; and   at least one leading edge cooling channel positioned proximate to the leading edge.   
     
     
         14 . The turbine airfoil of  claim 13 , further comprising at least one trailing edge exhaust orifice in fluid communication with the trailing edge cooling channel. 
     
     
         15 . The turbine airfoil of  claim 14 , further comprising at least one impingement rib in the trailing edge cooling channel that extends in a spanwise direction, wherein the impingement rib includes a plurality of impingement orifices. 
     
     
         16 . The turbine airfoil of  claim 15 , further comprising at least one leading edge supply channel in fluid communication with the at least one leading edge cooling channel. 
     
     
         17 . The turbine airfoil of  claim 16 , further comprising a plurality of impingement orifices in a rib separating the at least one leading edge supply channel from the at least one leading edge cooling channel. 
     
     
         18 . The turbine airfoil of  claim 13 , further comprising at least one trip strip in at least one of the legs of the serpentine cooling channel, wherein the at least one trip strip comprises a plurality of trip strips protruding from the outer walls forming the pressure side and a suction side of the generally elongated airfoil. 
     
     
         19 . The turbine airfoil of  claim 13 , further comprising a rib positioned in the trailing edge turn between the second and third legs. 
     
     
         20 . The turbine airfoil of  claim 19 , wherein the rib extends generally chordwise and contacts the trailing edge.