Turbine rotor blades having mid-span shrouds

Abstract

A rotor blade for use in a turbine of a combustion turbine engine is described. The rotor blade may include an airfoil that extends from a connection with a root. The rotor blade may further include a mid-span shroud configured to engage a corresponding mid-span shroud on at least one neighboring rotor blades during operation. Outboard of the mid-span shroud, the airfoil may include an outboard region that is substantially hollow, and inboard of the mid-span shroud, the airfoil may include an inboard region that is substantially solid.

1 . A rotor blade for use in a turbine of a combustion turbine engine, the rotor blade comprising an airfoil that extends from a connection with a root, the airfoil including a concave pressure sidewall and a convex suction sidewall extending axially between corresponding leading and trailing edges and radially between the root and an outboard tip, the rotor blade further comprising:
 a mid-span shroud configured to engage a corresponding mid-span shroud on at least one neighboring rotor blade during operation;   wherein:
 outboard of the mid-span shroud, the airfoil includes an outboard region that is substantially hollow; and 
 inboard of the mid-span shroud, the airfoil includes an inboard region that is substantially solid. 
   
     
     
         2 . The rotor blade of  claim 1 , wherein the mid-span shroud includes a circumferentially extending projection from at least one of the pressure sidewall and the suction sidewall of the airfoil. 
     
     
         3 . The rotor blade of  claim 1 , wherein the mid-span shroud comprises a circumferential projection from each of the pressure sidewall and the suction sidewall of the airfoil;
 wherein the mid-span shroud comprises a pressure side contact face at a distal end of the circumferential projection from the pressure sidewall and a suction side contact face at a distal end of the circumferential projection from the pressure sidewall;   wherein, upon installation, the pressure side contact face is configured to form a first shroud-to-shroud interface with the suction side contact face of a first neighboring rotor blade of a same design as the rotor blade; and   wherein, upon installation, the suction side contact face is configured to form a second shroud-to-shroud interface with the pressure side contact face of a second neighboring rotor blade of the same design as the rotor blade.   
     
     
         4 . The rotor blade of  claim 3 , wherein the mid-span shroud comprises a shroud that is positioned inboard of an outboard tip of the airfoil and outboard of a platform of the rotor blade. 
     
     
         5 . The rotor blade of  claim 3 , wherein the mid-span shroud comprises a shroud that is disposed within a range of positions on the airfoil; and wherein the range of positions is defined between an inboard boundary at 25% of a radial height of the airfoil and an outboard boundary at 75% of the radial height of the airfoil. 
     
     
         6 . The rotor blade of  claim 3 , wherein the mid-span shroud comprises a shroud that is disposed within a range of positions on the airfoil; and wherein the range of positions is defined between an inboard boundary at 33% of a radial height of the airfoil and an outboard boundary at 66% of the radial height of the airfoil. 
     
     
         7 . The rotor blade of  claim 5 , wherein the outboard region of airfoil comprises a portion of the airfoil that is outboard of the mid-span shroud, and wherein the inboard region of the airfoil comprises a portion of the airfoil that is inboard of the mid-span shroud;
 wherein a hollow region comprises a region within the airfoil that is hollow; and   wherein a solid region comprises a region within the airfoil that is solid material.   
     
     
         8 . The rotor blade of  claim 7 , wherein the hollow region of the outboard region of the airfoil comprises a hollow chamber. 
     
     
         9 . The rotor blade of  claim 8 , wherein the hollow chamber comprises a connector extending therethrough that structurally connects the pressure sidewall to the suction sidewall of the airfoil. 
     
     
         10 . The rotor blade of  claim 9 , wherein the connector comprises a plurality of ribs, a plurality of which extends across the hollow chamber from the suction sidewall to the pressure sidewall of the airfoil. 
     
     
         11 . The rotor blade of  claim 9 , wherein the connector comprises a plurality of pins, a plurality of which extends across the hollow chamber from the suction sidewall to the pressure sidewall of the airfoil. 
     
     
         12 . The rotor blade of  claim 9 , wherein the connector comprises an internal wall that divides the hollow chamber into a plurality of hollow chambers. 
     
     
         13 . The rotor blade of  claim 7 , wherein the outboard region of the airfoil comprises a hollowness percentage that defines what portion of a volume of the outboard region is the hollow region; and
 wherein the inboard region of the airfoil comprises a solidness percentage that defines what portion of a volume of the inboard region is the solid region.   
     
     
         14 . The rotor blade of  claim 13 , wherein the outboard region being substantially hollow is defined as the outboard region having a hollowness percentage of at least 70%; and
 wherein the inboard region being substantially solid is defined as the inboard region having the solidness percentage of at least 90%.   
     
     
         15 . The rotor blade of  claim 13 , wherein the outboard region being substantially hollow is defined as the outboard region having a hollowness percentage of at least 80%; and
 wherein the inboard region being substantially solid is defined as the inboard region having the solidness percentage of at least 95%.   
     
     
         16 . The rotor blade of  claim 13 , wherein the outboard region being substantially hollow is defined as the outboard region having a hollowness percentage of at least 90%; and
 wherein the inboard region being substantially solid is defined as the inboard region having the solidness percentage of 100%.   
     
     
         17 . The rotor blade of  claim 7 , wherein the solid region of the outboard region is limited to: a) a thin outer wall that along an inner surface defines a hollow chamber in the airfoil and along an outer surface defines the suction sidewall and pressure sidewall of the airfoil; and b) pins that span the hollow chamber structurally connecting the pressure sidewall to the suction sidewall; and
 wherein the hollow region of the inboard region is limited to narrow interior cooling passages configured to transport coolant across the inboard region from a coolant source formed through the root of the rotor blade to the hollow chamber of the outboard region.   
     
     
         18 . The rotor blade of  claim 7 , wherein the solid region of the outboard region is limited to a thin outer wall that along an inner surface defines a hollow chamber in the airfoil and along an outer surface defines the suction sidewall and pressure sidewall of the airfoil; and
 wherein the inboard region comprises no hollow region.   
     
     
         19 . The rotor blade of  claim 18 , wherein the outboard tip of the airfoil comprises a tip plate that encloses the hollow chamber of the airfoil. 
     
     
         20 . The rotor blade of  claim 19 , wherein the tip plate includes one or more film cooling apertures that, during operation, are configured to meter a release of the coolant flowing through the hollow chamber of the airfoil. 
     
     
         21 . The rotor blade of  claim 18 , wherein the outboard tip of the airfoil comprises an open face opening to the hollow chamber of the airfoil. 
     
     
         22 . A combustion turbine engine that includes:
 a rotor blade comprising an airfoil that extends from a connection with a root, the airfoil including a concave pressure sidewall and a convex suction sidewall extending axially between corresponding leading and trailing edges and radially between the root and an outboard tip, the rotor blade further comprising:
 a mid-span shroud configured to engage a corresponding mid-span shroud on at least one neighboring rotor blade during operation; 
 wherein, outboard of the mid-span shroud, the airfoil includes an outboard region that is substantially hollow, and, inboard of the mid-span shroud, the airfoil includes an inboard region that is substantially solid; 
 wherein a hollow region comprises a region within the airfoil that is hollow, and 
 wherein a solid region comprises a region within the airfoil that is solid material; 
 wherein the outboard region of the airfoil comprises a hollowness percentage that defines what portion of a volume of the outboard region is the hollow region; 
 wherein the inboard region of the airfoil comprises a solidness percentage that defines what portion of a volume of the inboard region is the solid region; and 
 wherein the outboard region being substantially hollow is defined as the outboard region having a hollowness percentage of at least 70% and wherein the inboard region being substantially solid is defined as the inboard region having the solidness percentage of at least 90%.