Patent ID: 6241467
Filing Date: 2001-06-05
Classification: F01D,F05B,F05D,Y02T

Abstract:
A coolable stator vane for a rotary machine having an axis A and a flowpath for working medium gases, the stator vane being adapted to be in flow communication with a supply plenum for a cooling fluid, the stator vane having an airfoil extending radially outwardly into the working medium flowpath, the airfoil having a leading edge, a trailing edge and flow directing surfaces which extend between the edges and which include a suction surface and a pressure surface, the stator vane having a rearmost rail adjacent the trailing edge which adapts the stator vane to engage a support, and further having structure which bounds the working medium flowpath, which comprises:a platform having a gas path surface for bounding the flowpath which hasa leading edge and a trailing edge which is spaced axially from the leading edge of the platform,a suction side and a pressure side which is spaced laterally from the suction side,a leading edge region forward of the airfoil, a midchord region from which the airfoil extends, and a trailing edge region extending rearwardly from the rearmost rail of the stator vane,a first wall in said trailing edge region which extends laterally between the sides, the first wall having an opening which adapts the platform to be in flow communication with said plenum,a second wall adjacent the trailing edge of the platform which extends laterally between the sides and which is spaced axially from the first wall leaving a cavity for cooling fluid therebetween,a pressure side wall which extends adjacent the pressure side of the vane platform from the first wall to the second wall to bound the cavity,a suction side wall which extends adjacent the suction side of the vane platform from the first wall to the second wall to bound the cavity anda rib which extends laterally from the pressure side wall toward the suction side wall and which is spaced axially from the first wall and the second wall to form a serpentine passage in the cavity for cooling fluid, the passage having a first pass and a second pass, the rib being spaced axially from the first wall and laterally from the suction side wall leaving a first turn region therebetween; and,a plurality of exit conduits which are adapted to duct the cooling fluid from the passage to the exterior of the platform, the plurality of exit conduits including at least one film cooling conduit in flow communication with the gas path surface of the platform and at least one trailing edge conduit which extends between the serpentine passage and the trailing edge of the platform;wherein the rib and the walls cooperate to form the serpentine passage having said two passes and legs disposed in serial fashion with respect to each other for sequentially receiving the flow of cooling fluid as the flow moves through the serpentine passage, the second pass adjacent the trailing edge of the platform receiving cooling fluid which has been heated during the first pass through an upstream portion of the trailing edge region of the platform; wherein a portion of the passage upstream of the rearmost pass is in flow communication with the surface of the platform through at least one film cooling conduit having a total cross sectional flow area Apfc and an associated flow characteristic Cpfc under operative conditions;wherein the rearmost pass is in flow communication with the platform surface through at least one film cooling conduit having a total cross sectional area Arfc and an associated flow characteristic Crfc under said operative conditions and is in flow communication with the trailing edge of the platform through at least one trailing edge conduit having a total cross sectional flow area Arte and an associated flow characteristic Crte for discharging cooling fluid entering the rearmost pass at the trailing edge of the platform; and, wherein the areas and associated flow characteristics are established such that more than sixty percent of the cooling fluid entering the serpentine passage is flowed from the rearmost leg to the exterior of the platform for cooling adjacent turbine structure and providing film cooling to the trailing edge of the platform such that less than forty percent of the cooling fluid entering the serpentine passage is injected upstream of the rearmost leg into the flowpath for working medium gases under an operative condition of the engine and wherein the turn region is located at a location adjacent the suction side wall of the platform to increase convective cooling at this location.