Turbine rotor blade platform cooling

Abstract

A cooling arrangement in a platform in a rotor blade or a sidewall in a stator blade in a turbine of a combustion turbine engine is described. The cooling arrangement may include: a cooling chamber configured to pass coolant from an inlet to an outlet; and a rib positioned within the cooling chamber. The rib may partially divide the cooling chamber so to form a switchback. The rib may be canted with respect to the cooling chamber such that the switchback has an ever narrowing channel.

We claim: 
     
         1 . A cooling arrangement in one of a sidewall of a stator blade and a platform in a rotor blade in a turbine of a combustion turbine engine, the cooling arrangement comprising:
 a cooling chamber configured to pass coolant from an inlet to an outlet; and   a rib positioned within the cooling chamber, the rib partially dividing the cooling chamber so to form a switchback;   wherein the rib is canted with respect to the cooling chamber such that the switchback comprises an ever narrowing channel.   
     
     
         2 . The cooling arrangement according to  claim 1 , wherein ever narrowing channel comprises a channel that narrows at a constant rate as the channel extends from the inlet to the outlet of the cooling chamber. 
     
     
         3 . The cooling arrangement according to  claim 1 , wherein the ever narrowing channel comprises a channel that narrows at a constant rate along both flanks of the rib. 
     
     
         4 . The cooling arrangement according to  claim 3 , wherein the switchback comprises a pass positioned on each flank of the rib: an upstream pass disposed on a flank of the rib that coincides with the inlet; and a downstream pass disposed on a flank of the rib that coincides with the outlet; and
 wherein, between the upstream pass and the downstream pass, the switchback comprises a turn section that defines a turn of approximately 180°.   
     
     
         5 . The cooling arrangement according to  claim 4 , wherein the cooling chamber comprises a first edge and a second edge, wherein the second edge opposes the first edge across the cooling chamber;
 wherein the rib extends linearly between a first end, which is positioned on the first edge of the cooling chamber between the inlet and outlet, and a second end, which is offset a distance from the second edge of the cooling chamber.   
     
     
         6 . The cooling arrangement according to  claim 5 , wherein:
 the rib is canted such that: a channel width of the upstream pass decreases at a linear rate as the upstream pass extends from the inlet to the second end of the rib; and a channel width of the downstream pass decreases at a linear rate as the downstream pass extends from the second end of the rib to the outlet; and   a channel width of a downstream end of the upstream pass is just greater than a channel width of an upstream end of the downstream pass.   
     
     
         7 . The cooling arrangement according to  claim 1 , wherein the cooling chamber comprises a planar configuration and an outboard profile of a quadrilateral; and
 wherein the rib is linear.   
     
     
         8 . The cooling arrangement according to  claim 7 , wherein the quadrilateral comprises a first pair and a second pair of opposing edges, each pair comprising two of the sides of the quadrilateral that oppose each other across the cooling chamber;
 wherein the first pair of opposing edges includes a first edge and a second edge, and the second pair of opposing edges includes a third edge and a fourth edge; and   wherein the inlet and the outlet are disposed on the first edge, and, between the inlet and the outlet, a first end of the rib is positioned on the first edge.   
     
     
         9 . The cooling arrangement according to  claim 8 , wherein, from the first end, the rib extends toward the second edge, the rib terminating at a second end;
 wherein the second end of the rib is offset a distance from the second edge.   wherein the third edge is parallel to the fourth edge; and   wherein the rib is canted with respect to a direction of a longitudinal axis of the cooling chamber that is defined by midpoints defined between the third and fourth edge.   
     
     
         10 . The cooling arrangement according to  claim 9 , wherein the rib is canted toward the third edge such that, as the rib extends from the first edge toward the second edge, a distance between the rib and the third edge decreases by a linear rate while a distance between the rib and the fourth edge increases by the linear rate. 
     
     
         11 . The cooling arrangement according to  claim 10 , wherein the angle defined between the rib and the direction of the longitudinal axis of the cooling chamber is between 0° and 30°. 
     
     
         12 . The cooling arrangement according to  claim 10 , wherein the angle defined between the rib and the longitudinal axis of the cooling chamber is between 0° and 60°;
 wherein the switchback comprises: a) an inlet channel width, which represents the channel width of the switchback at the inlet; b) a pre-turn channel width, which represents the channel width of the switchback between the second end of the rib and the third edge; c) a post-turn channel width, which represent the channel width of the switchback between the second end of the rib and the fourth edge; and d) an outlet channel width, which represents the channel width of the switchback path at the outlet; and 
 wherein the ever narrowing channel comprises a configuration in which the inlet width is greater than the pre-turn width; the pre-turn width is greater than the post-turn width; and the post-turn width is greater than the outlet channel width. 
 
     
     
         13 . The cooling arrangement according to  claim 12 , wherein, between the pre-turn channel width and the post-turn channel width, the switchback comprises a turn-section within which a turn-section channel width represents a channel width of the switchback between the second end of the rib and the second edge of the cooling chamber;
 wherein the ever narrowing channel comprises a configuration in which the turn-section channel width is less than the pre-turn channel width and greater than the post-turn channel width.   
     
     
         14 . The cooling arrangement according to  claim 12 , wherein the ever narrowing channel along both of the flanks of the rib comprises:
 the channel width of the switchback decreasing at a constant linear rate between the inlet channel width and the pre-turn channel width; and   the channel width of the switchback decreasing at a constant linear rate between the post-turn channel width and the outlet channel width.   
     
     
         15 . The cooling arrangement according to  claim 9 , wherein the outboard profile of the cooling chamber comprises a parallelogram. 
     
     
         16 . The cooling arrangement according to  claim 9 , wherein the one of the platform and the sidewall comprises a planar configuration and wherein the cooling chamber comprises a planar configuration that is aligned with the planar configuration of the one of the platform and the sidewall and contained therein. 
     
     
         17 . The cooling arrangement according to  claim 9 , wherein the one of the platform and the sidewall comprises a planar topside;
 wherein the cooling chamber comprises a planar ceiling that is just inboard of the topside and a planar floor radially offset from the ceiling, and   wherein a radial height of the cooling chamber comprises the radial offset between the ceiling and the floor; and   wherein the radial height of the cooling chamber is constant.   
     
     
         18 . The cooling arrangement according to  claim 9 , wherein the cooling arrangement is disposed in the platform of the rotor blade;
 wherein the rotor blade includes an interior cooling passage formed therein that extends from a connection with a coolant source at the root to the approximate radial height of the platform, wherein, in operation, the interior cooling passage comprises a high-pressure coolant region and a low-pressure coolant region;   further comprising:
 a high-pressure connector that connects the inlet to the high-pressure coolant region of the interior cooling passage; 
 a low-pressure connector that connects the outlet to the low-pressure coolant region of the interior cooling passage. 
   
     
     
         19 . The cooling arrangement according to  claim 9 , wherein the cooling arrangement is disposed in the platform of the rotor blade;
 wherein the rotor blade includes an interior cooling passage formed therein that extends from a connection with a coolant source at the root to the approximate radial height of the platform;   further comprising:
 a connector that connects the inlet to the interior cooling passage; and 
 a plurality of film cooling ports that fluidly communicate with the outlet. 
   
     
     
         20 . A cooling arrangement in a platform of a rotor blade in a turbine of a combustion turbine engine, the cooling arrangement comprising:
 a cooling chamber configured to pass coolant from an inlet to an outlet; and   a rib positioned within the cooling chamber, the rib partially dividing the cooling chamber so to form a switchback;   wherein the rib is canted with respect to the cooling chamber such that the switchback comprises an ever narrowing channel.   
     
     
         21 . A cooling arrangement in a sidewall of a stator blade in a turbine of a combustion turbine engine, the cooling arrangement comprising:
 a cooling chamber configured to pass coolant from an inlet to an outlet; and   a rib positioned within the cooling chamber, the rib partially dividing the cooling chamber so to form a switchback;   wherein the rib is canted with respect to the cooling chamber such that the switchback comprises an ever narrowing channel.