Cooling arrangement for platform region of turbine rotor blade

Abstract

A platform cooling arrangement in a turbine rotor blade having a platform at an interface between an airfoil and a root. The platform may include a pressure side slashface and a suction side slashface. The platform cooling arrangement may include: a cooling channel formed within the interior of the platform, the cooling channel extending from a first end toward one of the pressure side slashface and the suction side slashface. At a second end, the cooling channel may include a pocket. The pocket may include an abrupt increase in cross-sectional flow area just before the cooling channel reaches the slashface.

We claim: 
     
         1 . A platform cooling arrangement in a turbine rotor blade having a platform at an interface between an airfoil and a root, wherein the platform comprises a pressure side slashface and a suction side slashface, the platform cooling arrangement comprising:
 a cooling channel formed within the interior of the platform, the cooling channel extending from a first end toward one of the pressure side slashface and the suction side slashface;   wherein, at a second end, the cooling channel comprises a pocket, the pocket comprises an abrupt increase in cross-sectional flow area just before the cooling channel reaches the one of the pressure side slashface and the suction side slashface.   
     
     
         2 . The platform cooling arrangement according to  claim 1 , wherein the first end of the cooling channel connects to a port formed at an underside of the platform, the port configured to fluidly communicate with a shank cavity cooling source during operation. 
     
     
         3 . The platform cooling arrangement according to  claim 3 , wherein the first end of the cooling channel connects to a plenum formed within the interior of the platform, the plenum comprising a cross-sectional flow area greater than a cross-sectional flow area of the cooling channel. 
     
     
         4 . The platform cooling arrangement according to  claim 3 , wherein the rotor blade includes an interior cooling passage formed therein that extends from a connection with a coolant source at the root of the rotor blade to at least the approximate radial height of the platform;
 further comprising a connector that connects the plenum to the interior cooling passage.   
     
     
         5 . The platform cooling arrangement according to  claim 3 , further comprising a plurality of cooling channels;
 wherein each of the plurality of cooling channels connects to the plenum at the first end; and   wherein, at the second end, each of the plurality of cooling channels includes the pocket, each of the pockets comprising an abrupt increase in cross-sectional flow area just before the cooling channel reaches the one of the pressure side slashface and the suction side slashface.   
     
     
         6 . The platform cooling arrangement according to  claim 5 , wherein the plurality of pockets are disposed along the suction side slashface. 
     
     
         7 . The platform cooling arrangement according to  claim 5 , wherein the plurality of pockets are disposed at regular intervals along the pressure side slashface; and
 wherein the plurality of pockets comprises between 4 and 8 pockets.   
     
     
         8 . The platform cooling arrangement according to  claim 5 , wherein the plurality of pockets are dispersed along the pressure side slashface; and
 wherein each of the plurality of pockets comprises a concave depression formed in the pressure side slashface.   
     
     
         9 . The platform cooling arrangement according to  claim 8 , wherein each of the plurality of pockets includes a mouth coplanar to the pressure side slashface;
 wherein, from the mouth, each of the pockets extends into the platform a short distance and terminates at an inner wall, the inner wall residing opposite the mouth;   wherein each of the pockets comprises a port through which coolant traveling through the cooling channel enters the pocket; and   wherein the port is disposed on the inner wall of the pocket.   
     
     
         10 . The platform cooling arrangement according to  claim 9 , wherein the mouth of each of the plurality of pockets comprises a rectangular profile. 
     
     
         11 . The platform cooling arrangement according to  claim 9 , wherein each of the pockets comprises:
 a depth that defines a circumferential distance between the mouth and the inner wall;   a height that defines a radial height of the pocket;   a width that is an axial width of the pocket;   wherein the pocket is configured such that the depth comprises 0.1 and 0.6 times a circumferential depth of the platform;   wherein the height of the pocket is between 0.1 and 0.9 times a radial height of the platform;   wherein the width of the pocket is between 0.1 and 0.4 times an axial width of the platform; and   wherein the port comprises a cross-sectional flow area that is between 0.1 and 0.6 times a cross-sectional flow area of the mouth.   
     
     
         12 . The platform cooling arrangement according to  claim 9 , wherein each of the pockets comprises:
 a depth that defines a circumferential distance between the mouth and the inner wall;   a height that defines a radial height of the pocket;   a width that is an axial width of the pocket;   wherein the pocket is configured such that the depth comprises 0.2 and 0.3 times a circumferential depth of the platform;   wherein the height of the pocket is between 0.4 and 0.8 times a radial height of the platform; and   wherein the width of the pocket is between 0.2 and 0.3 times an axial width of the platform; and   wherein the port comprises a cross-sectional flow area that is between 0.2 and 0.4 times a cross-sectional flow area of the mouth.   
     
     
         13 . The platform cooling arrangement according to  claim 8 , wherein the mouth comprises a greater cross-sectional flow area than both the port and the cooling channel. 
     
     
         14 . The platform cooling arrangement according to  claim 8 , further comprising a pocket-to-pocket channel, the pocket-to-pocket channel comprising an interior channel that connects one of the plurality of pockets to a neighboring pocket. 
     
     
         15 . The platform cooling arrangement according to  claim 14 , wherein the pocket-to-pocket channel is parallel to the pressure side slashface and configured to allow fluid communication between the one pocket and the neighboring pocket. 
     
     
         16 . The platform cooling arrangement according to  claim 14 , wherein the pocket-to-pocket channel comprises a cross-sectional flow area that is less than the cross-sectional flow area of the mouth of each of the one pocket and the neighboring pocket. 
     
     
         17 . The platform cooling arrangement according to  claim 8 , further comprising a pocket-to-topside channel, the pocket-to-topside channel comprising an interior channel that connects one of the plurality of pockets to a topside of the platform. 
     
     
         18 . The platform cooling arrangement according to  claim 17 , wherein the pocket-to-topside channel is configured to allow fluid communication between a port located on an outboard inner surface of the pocket and a topside port formed on the topside of the platform. 
     
     
         19 . The platform cooling arrangement according to  claim 17 , wherein the pocket-to-topside channel comprises a cross-sectional flow area that is less than the cross-sectional flow area of the mouth of the pocket; and
 wherein the pocket-to-topside channel is canted in a downstream direction.   
     
     
         20 . The platform cooling arrangement according to  claim 5 , wherein the plenum comprises a hollow passageway, the plenum extending from an interior position to a position near one of the pressure side slashface and the suction side slashface;
 wherein the plenum includes an plenum outlet that connects to another pocket formed on the one of the pressure side slashface and the suction side slashface; and   wherein the plenum outlet comprises a cross-sectional flow area that is less than the cross-sectional flow area of the plenum.   
     
     
         21 . The platform cooling arrangement according to  claim 20 , wherein the cross-sectional flow area of the plenum outlet is configured such that a desired metering characteristic is achieved. 
     
     
         22 . The platform cooling arrangement according to  claim 21 , further comprising a non-integral plug positioned between the plenum and the pocket, the non-integral plug configured to reduce the cross-sectional flow area of the plenum so to form the plenum outlet. 
     
     
         23 . The platform cooling arrangement according to  claim 5 , wherein
 the plenum comprises a supply chamber from which the plurality of cooling channels branch; and   each of the plurality of cooling channels comprises a linear passageway that extends between the plenum and one of the pockets.   
     
     
         24 . The platform cooling arrangement according to  claim 23 , further comprising a plurality of plenums, each of which includes a plurality of cooling channels branching therefrom. 
     
     
         25 . A platform cooling arrangement in a turbine rotor blade having a platform at an interface between an airfoil and a root, wherein the rotor blade includes an interior cooling passage formed therein that extends from a connection with a coolant source at the root to at least the approximate radial height of the platform, wherein, along a side that coincides with a pressure side of the airfoil, a pressure side of the platform comprises a topside extending circumferentially from the airfoil to a pressure side slashface, and along a side that coincides with a suction side of the airfoil, a suction side of the platform comprises a topside extending circumferentially from the airfoil to a suction side slashface, the platform cooling arrangement comprising:
 a plenum residing just inboard of the planar topside and extending from an interior position to a position near one of the pressure side slashface and the suction side slashface of the platform, the plenum having a longitudinal axis that is approximately parallel to the planar topside;   a connector that is configured to fluidly connect the plenum and the interior cooling passage; and   a plurality of cooling channels, each of which includes, at a first end, a connection with the plenum and, at a second end, a pocket formed at the one of the pressure side slashface and the suction side slashface;   wherein each of the pockets includes an abrupt increase in cross-sectional flow area of the cooling channel, the abrupt increase in cross-sectional flow area extending from a port formed along an inner wall of the pocket to a mouth coplanar to the one of the pressure side slashface and the suction side slashface over.