Rotor blade cooling flow

Abstract

A rotor blade includes and airfoil. The airfoil includes pressure and suction side walls which extend radially outwardly from a platform in span from a root to a tip and between a leading edge and a trialing edge. The tip includes a tip floor, a plurality of coolant outlets and a tip rail having a pressure side and suction side portions that extend radially outwardly from the tip floor. Cooling passages are circumscribed within the airfoil and are in fluid communication with one or more of the coolant outlets. A baffle extends radially outwardly from and transversely across the tip floor from the pressure side portion to the suction side portion to define first and second tip pockets. A slot is disposed along the suction side portion of the tip rail to provide for fluid communication out of one of the first or second tip pockets, thereby reducing pressure within the corresponding tip pocket.

What is claimed is: 
     
         1 . A rotor blade, comprising:
 an airfoil including pressure and suction side walls which extend radially outwardly from a platform in span from a root to a tip and in chord between a leading edge and a trialing edge, the tip including a tip floor and a plurality of coolant outlets disposed along the tip floor, the tip further including a tip rail that extends radially outwardly from the tip floor, the tip rail having a pressure side portion and a suction side portion which are joined at the leading and trailing edges;   a plurality of cooling passages circumscribed within the airfoil for routing a coolant therethrough, each of the cooling passages being in fluid communication with one or more of the coolant outlets;   a baffle extending radially outwardly from and across the tip floor from the pressure side portion to the suction side portion to define a first tip pocket and a second tip pocket; and   a slot disposed along the suction side portion of the tip rail, wherein the slot provides for fluid communication out of one of the first or second tip pockets.   
     
     
         2 . The rotor blade as in  claim 1 , wherein the slot extends radially outwardly from the tip floor. 
     
     
         3 . The rotor blade as in  claim 1 , wherein at least one of the coolant outlets is disposed along the tip floor within the first tip pocket. 
     
     
         4 . The rotor blade as in  claim 1 , wherein at least one of the coolant outlets is disposed along the tip floor within the second tip pocket. 
     
     
         5 . The rotor blade as in  claim 1 , further comprising an opening formed in the baffle, wherein the opening provides for fluid communication between the first tip pocket and the second tip pocket. 
     
     
         6 . The rotor blade as in  claim 1 , wherein the baffle is configured to allow a portion of the coolant to flow over a top portion of the baffle into an adjacent tip pocket. 
     
     
         7 . The rotor blade as in  claim 1 , further comprising a secondary baffle extending radially outwardly from and across the tip floor from the pressure side portion to the suction side portion to define a third tip pocket. 
     
     
         8 . The rotor blade as in  claim 7 , further comprising a slot disposed along the suction side portion of the tip rail, wherein the slot provides for fluid communication out of the third tip pocket. 
     
     
         9 . A system for promoting coolant flow through a rotor blade, comprising:
 a coolant source for supplying a pressurized coolant to a cooling passage inlet formed along the rotor blade; and   wherein the rotor blade comprises:
 a mounting portion including a mounting body, the mounting body being interconnectable with a rotor shaft, at least one of the cooling passage inlets being formed by the mounting body; 
 an airfoil coupled to the mounting portion and including pressure and suction side walls which extend radially outwardly from a platform in span from a root to a tip and in chord between a leading edge and a trialing edge, the tip including a tip floor and a plurality of coolant outlets disposed along the tip floor, the tip further including a tip rail that extends radially outwardly from the tip floor, the tip rail having a pressure side portion and a suction side portion which are joined at the leading and trailing edges; 
 a plurality of cooling passages circumscribed within the airfoil for routing a coolant through the airfoil, each of the cooling passages being in fluid communication with one or more of the coolant inlets; 
 a baffle extending radially outwardly from and across the tip floor from the pressure side portion to the suction side portion to define a first tip pocket and a second tip pocket; and 
 a slot disposed along the suction side portion of the tip rail, wherein the slot provides for fluid communication out of one of the first or second tip pockets. 
   
     
     
         10 . The system as in  claim 9 , wherein the slot extends radially outwardly from the tip floor. 
     
     
         11 . The system as in  claim 9 , wherein at least one coolant outlet is disposed along the tip floor within the first tip pocket and at least one coolant outlet is disposed along the tip floor within the second tip pocket. 
     
     
         12 . The system as in  claim 9 , further comprising a coolant opening formed in the baffle, wherein the coolant opening provides for fluid communication between the first tip pocket and the second tip pocket. 
     
     
         13 . The system as in  claim 9 , wherein the baffle is configured to allow a portion of the coolant to flow over a top portion of the baffle into an adjacent tip pocket. 
     
     
         14 . The system as in  claim 9 , further comprising a secondary baffle extending radially outwardly from and across the tip floor from the pressure side portion to the suction side portion to define a third tip pocket. 
     
     
         15 . The system as in  claim 14 , further comprising a secondary slot disposed along the suction side portion of the tip rail, wherein the secondary slot provides for fluid communication out of the third tip pocket. 
     
     
         16 . A gas turbine, comprising;
 a compressor;   a combustor disposed downstream from the compressor;   a turbine disposed downstream from the combustor, the turbine including a rotor shaft extending axially through the turbine, an outer casing circumferentially surrounding the rotor shaft to define a hot gas path therebetween and a plurality of rotor blades interconnected to the rotor shaft and defining a stage of rotor blades, wherein each rotor blade comprises;
 a mounting portion including a mounting body, the mounting body being interconnectable with a rotor shaft, at least one of the cooling passage inlets being formed by the mounting body; 
 an airfoil coupled to the mounting portion and including pressure and suction side walls which extend radially outwardly from a platform in span from a root to a tip and in chord between a leading edge and a trialing edge, the tip including a tip floor and a plurality of coolant outlets disposed along the tip floor, the tip further including a tip rail that extends radially outwardly from the tip floor, the tip rail having a pressure side portion and a suction side portion which are joined at the leading and trailing edges; 
 a plurality of cooling passages circumscribed within the airfoil for routing a coolant through the airfoil, each of the cooling passages being in fluid communication with one or more of the coolant inlets; 
 a baffle extending radially outwardly from and transversely across the tip floor from the pressure side portion to the suction side portion to define a first tip pocket and a second tip pocket, wherein at least one coolant outlet is disposed along the tip floor within the first tip pocket and at least one coolant outlet is disposed along the tip floor within the second tip pocket; and 
 a slot disposed along the suction side portion of the tip rail, wherein the slot provides for fluid communication out of one of the first or second tip pockets. 
   
     
     
         17 . The gas turbine as in  claim 16 , wherein the slot extends radially outwardly from the tip floor. 
     
     
         18 . The gas turbine as in  claim 16 , further comprising a slot formed in the baffle, wherein the slot provides for fluid communication between the first tip pocket and the second tip pocket. 
     
     
         19 . The gas turbine as in  claim 16 , wherein the baffle is sized to allow a portion of the coolant to flow over a top portion of the baffle into an adjacent tip pocket. 
     
     
         20 . The gas turbine as in  claim 16 , further comprising a secondary baffle extending radially outwardly from and across the tip floor from the pressure side portion to the suction side portion to define a third tip pocket, wherein a secondary slot is disposed along the suction side portion of the tip rail, wherein the secondary slot provides for fluid communication out of the third tip pocket.