Interior cooling circuits in turbine blades

Abstract

An airfoil of a turbine rotor blade that includes a cooling configuration having a plurality of elongated flow passages for receiving and directing a coolant along a path through the airfoil. The cooling configuration may include: a central flow passage flanked to each side by near-wall flow passages that includes a pressure side near-wall flow passage and a suction side near-wall flow passage; a first port that fluidly connects the central flow passage to the pressure side near-wall flow passage; a second port that fluidly connects the central flow passage to the suction side near-wall flow passage; and impingement connectors that fluidly connect the central flow passage to a leading edge flow passage.

We claim: 
     
         1 . A turbine blade, comprising:
 an airfoil having a leading edge, a trailing edge, an outboard tip, and an inboard end where the airfoil attaches to a root configured to couple the turbine blade to a disc, wherein the airfoil further includes a cooling configuration comprising a plurality of elongated flow passages for receiving and directing a coolant along a path through the airfoil, the cooling configuration comprising:   a central flow passage flanked to each side by near-wall flow passages that includes a pressure side near-wall flow passage and a suction side near-wall flow passage;   a first port that fluidly connects the central flow passage to an upstream portion of the pressure side near-wall flow passage;   a second port that fluidly connects the central flow passage to an upstream portion of the suction side near-wall flow passage;   a leading edge flow passage; and   impingement connectors that fluidly connect the central flow passage to the leading edge flow passage.   
     
     
         2 . The turbine blade according to  claim 1 , wherein the leading edge flow passage is positioned in close proximity to the leading edge of the airfoil, the leading edge flow passage extending radially outward in spaced relation to the leading edge of the airfoil from a first end positioned near the inboard end of the airfoil to a second end positioned near the outboard tip of the airfoil. 
     
     
         3 . The turbine blade according to  claim 2 , wherein the impingement connectors to allow coolant to pass from the central flow passage to the leading edge flow passage and impinge on an inner surface of the wall forming the leading edge. 
     
     
         4 . The turbine blade according to  claim 3 , wherein the leading edge flow passage comprises surface outlets through which the coolant is exhausted from the turbine blade. 
     
     
         5 . The turbine blade according to  claim 3 , wherein the plurality of impingement connectors are radially spaced between the first and second end of the leading edge flow passage. 
     
     
         6 . The turbine blade according to  claim 2 , wherein the pressure side near-wall flow passage includes axially-stacked and parallel first and second flow passages, each of which have an inner wall defined by the pressure side outer wall of the airfoil. 
     
     
         7 . The turbine blade according to  claim 6 , wherein the suction side near-wall flow passage includes axially-stacked and parallel first and second flow passages, each of which have an inner wall defined by the suction side outer wall of the airfoil. 
     
     
         8 . The turbine blade according to  claim 1 , wherein the pressure side near-wall flow passage comprises a switchback circuit that includes: a first segment that extends radially outward from a first end positioned near the inboard end of the airfoil to a second end positioned near the outboard end of the airfoil; a second segment that extends radially inward from a first end positioned near the outboard end of the airfoil to a second end positioned near the inboard end of the airfoil; and a crossover passage that, near the outboard end of the airfoil, fluidly connects the second end of the first segment to the first end of the second segment. 
     
     
         9 . The turbine blade according to  claim 8 , wherein the suction side near-wall flow passage comprises a switchback circuit that includes: a first segment that extends radially outward from a first end positioned near the inboard end of the airfoil to a second end positioned near the outboard end of the airfoil; a second segment that extends radially inward from a first end positioned near the outboard end of the airfoil to a second end positioned near the inboard end of the airfoil; and a crossover passage that, near the outboard end of the airfoil, fluidly connects the second end of the first segment to the first end of the second segment. 
     
     
         10 . The turbine blade according to  claim 9 , wherein the first and second segments of the pressure side near-wall flow passage share a common, partitioning wall that is configured so to maintain a fixed spaced relation therebetween; and
 wherein the first and second segments of the suction side near-wall flow passage share a common, partitioning wall that is configured so to maintain a fixed spaced relation therebetween;   further comprising a sinusoidal tip flow passage that connects to at least one of the crossover passages.   
     
     
         11 . The turbine blade according to  claim 9 , wherein the first and second segments of the pressure side near-wall flow passage are partitioned by a traverse rib that connects the pressure side outer wall to a camber line rib; and
 wherein the first and second segments of the suction side near-wall flow passage are partitioned by a traverse rib that connects the suction side outer wall to a camber line rib.   
     
     
         12 . The turbine blade according to  claim 9 , wherein the first port is disposed near the second end of the second segment of the pressure side near-wall flow passage, and the second port is disposed near the second end of the second segment of the pressure side near-wall flow passage. 
     
     
         13 . The turbine blade according to  claim 9 , wherein the first end of the first segment of the pressure side near-wall flow passage comprises a connection to a coolant feed passage formed through the root of the turbine blade; and
 wherein the first end of the first segment of the suction side near-wall flow passage comprises a connection to a coolant feed passage formed through the root of the turbine blade.   
     
     
         14 . The turbine blade according to  claim 1 , wherein the turbine blade comprises a turbine rotor blade, and wherein the cooling configuration comprises a position near the leading edge of the airfoil. 
     
     
         15 . The turbine blade according to  claim 1 , wherein the central flow passage, the pressure side near-wall flow passage, the suction side near-wall flow passage, and the leading edge flow passage are disposed between the leading edge of the airfoil and a midpoint of a camber line of the airfoil. 
     
     
         16 . A turbine blade comprising an airfoil defined by a concave shaped pressure side outer wall and a convex shaped suction side outer wall that connect along leading and trailing edges and, therebetween, form a radially extending chamber for receiving the flow of a coolant, wherein the chamber includes a cooling configuration having:
 three laterally stacked flow passages positioned between the pressure side outer wall and the suction side outer wall: a pressure side near-wall flow passage disposed adjacent to the pressure side outer wall; a suction side near-wall flow passage disposed adjacent to the suction side outer wall; and a central plenum disposed between the pressure side near-wall flow passage and the suction side near-wall flow passage; and   a leading edge flow passage that is positioned in close proximity and parallel to the leading edge of the airfoil;   wherein ports fluidly connect the central flow passage to a downstream portion of the pressure side near-wall flow passage and a downstream portion of the suction side near-wall flow passage; and   wherein impingement connectors fluidly connect the central flow passage to the leading edge flow passage.   
     
     
         17 . The turbine blade according to  claim 16 , wherein the pressure side near-wall flow passage comprises an axially-stacked two-pass serpentine circuit, wherein each pass includes an inner wall that makes contact with the pressure side outer wall; and
 wherein the suction side near-wall flow passage comprises an axially-stacked two-pass serpentine circuit, wherein each pass includes an inner wall that makes contact with the suction side outer wall.   
     
     
         18 . The turbine blade according to  claim 17 , wherein the two-pass serpentine circuit of the pressure side near-wall flow passage comprises a 180 degree turn near an outboard tip of the airfoil; and
 wherein the two-pass serpentine circuit of the suction side near-wall flow passage comprises a 180 degree turn near the outboard tip of the airfoil.   
     
     
         19 . The turbine blade according to  claim 18 , wherein each of an upstream end and the downstream portion of the two-pass serpentine circuit of the pressure side near-wall flow passage comprises a position near an inboard end of the airfoil; and
 wherein each of an upstream end and the downstream portion of the two-pass serpentine circuit of the suction side near-wall flow passage comprises a position near the inboard end of the airfoil.   
     
     
         20 . The turbine blade according to  claim 16 , further comprising a plurality of exhaust orifices in the leading edge flow passage for exhausting the coolant onto an exterior surface of the airfoil;
 wherein the impingement connectors are adapted to allow coolant to pass from the central flow passage to the leading edge flow passage and impinge on an inner surface of the wall forming the leading edge.