Tear-drop shaped part-span shroud

Abstract

A rotatable blade for use in a turbomachine includes an airfoil portion having a leading edge, a trailing edge a radially-inner end and a radially-outer end; a root section affixed to the radially-inner end of the airfoil portion. A part-span shroud is located on the airfoil portion between the root section and the radially-outer end. The part-span shroud is substantially tear-drop shaped such that its cross-sectional shape has a maximum thickness located within 20 to 40% of a chord length extending between leading and trailing edges of the part-span shroud, as measured from the leading edge of the part-span shroud.

What is claimed is: 
     
         1 . A rotatable blade for a turbomachine comprising:
 an airfoil portion having a leading edge and a trailing edge, a radially-inner end and a radially-outer end;   a root section affixed to the radially-inner end of the airfoil portion; and   a substantially tear-drop shaped part-span shroud located on the airfoil portion between the root section and the radially outer end, wherein said part-span shroud is provided with a cross-sectional shape having a maximum thickness located within 20 to 40% of a chord length extending from a leading edge of said part-span shroud to a trailing edge of said part-span shroud, as measured from said leading edge of said part-span shroud.   
     
     
         2 . The rotatable blade of  claim 1 , wherein said maximum thickness is located at about 30% of said chord length. 
     
     
         3 . The rotatable blade of  claim 1 , wherein said said maximum thickness is located between 31% and 37% of said chord length. 
     
     
         4 . The rotatable blade of  claim 1 , wherein said maximum thickness is located at 31% of said chord length and wherein said part-span shroud has a profile defined by the X-Y coordinates set forth in Table I. 
     
     
         5 . The rotatable blade of  claim 1 , wherein said maximum thickness is located at 36% of said chord length and wherein said part-span shroud has a profile defined by the X-Y coordinates set forth in Table II. 
     
     
         6 . The rotatable blade of  claim 1 , wherein said maximum thickness is located at 37% of said chord length and wherein said part-span shroud has a profile defined by the X-Y coordinates set forth in Table III. 
     
     
         7 . The rotatable blade of  claim 1  wherein the part-span shroud is located substantially midway along a radial length of the airfoil portion. 
     
     
         8 . The rotatable blade of  claim 1  wherein the rotating blade operates as one of:
 a front stage blade in a compressor, 
 a latter stage blade in a gas turbine, or 
 a low pressure section blade in a steam turbine. 
 
     
     
         9 . The rotatable blade of  claim 1  wherein part-span shrouds on respective pressure and suction sides of adjacent ones of said blades at least partially engage along adjacent, substantially Z-shaped contact surfaces. 
     
     
         10 . The rotatable blade of  claim 1  wherein part-span shrouds on respective pressure and suction sides of adjacent ones of said blades have substantially-straight contact surfaces. 
     
     
         11 . A turbomachine comprising:
 a rotor rotatably mounted within a stator, the rotor including:   a shaft;   at least one rotor wheel mounted on the shaft, each of the at least one rotor wheels including a plurality of radially outwardly extending blades mounted thereon; and   wherein each blade includes an airfoil portion having a leading edge and a trailing edge, a radially-inner end and a radially-outer end, a pressure side and a suction side; a root section at the radially-inner end of said airfoil portion; and a part-span shroud located on said airfoil portion between said root section and said radially outer end, on said pressure side and said suction side, wherein said part-span shroud is provided with a substantially tear-drop cross-sectional shape having a maximum thickness located within 20 to 40% of a chord length extending between a leading edge of said part-span shroud and a trailing edge of said part-span shroud, as measured from said leading edge of said part-span shroud.   
     
     
         12 . The turbomachine of  claim 11  wherein said maximum thickness is located at 31% of said chord length and wherein said part-span shroud has a profile defined by the X-Y coordinates set forth in Table I. 
     
     
         13 . The turbomachine of  claim 11 , wherein said maximum thickness is located at 36% of said chord length and wherein said part-span shroud has a profile defined by the X-Y coordinates set forth in Table II. 
     
     
         14 . The turbomachine of  claim 11 , wherein said maximum thickness is located at 37% of said chord length and wherein said part-span shroud has a profile defined by the X-Y coordinates set forth in Table III. 
     
     
         15 . The turbomachine of  claim 11 , wherein said blade operates as one of:
 a front stage blade in a compressor,   a latter stage blade in a gas turbine, or   a low pressure section blade in a steam turbine.   
     
     
         16 . The turbomachine of  claim 11  wherein said part-span shroud is located substantially midway along a radial length of said airfoil portion. 
     
     
         17 . A turbomachine comprising:
 a rotor rotatably mounted within a stator, the rotor including:   a shaft;   at least one rotor wheel mounted on the shaft, each of the at least one rotor wheels including a plurality of radially outwardly extending blades mounted thereon; and   wherein each blade includes an airfoil portion having a leading edge and a trailing edge, a radially-inner end and a radially-outer end, a pressure side and a suction side; a root section at the radially-inner end of said airfoil portion; and a part-span shroud located on said airfoil portion between said root section and said radially outer end, on said pressure side and said suction side, wherein said part-span shroud is provided with a substantially tear-drop cross-sectional shape having a maximum thickness located at 31%, 36% or 37% of a chord length extending between a leading edge of said part-span shroud and a trailing edge of said part-span shroud, as measured from said leading edge of said part-span shroud; and wherein said part-span shroud is disposed on the airfoil portion between about 40% to 80% of a radial height of said airfoil portion as measured from the root section of the blade.   
     
     
         18 . The turbomachine of  claim 17  wherein said part-span shroud has a profile defined by the X-Y coordinates as set forth in any one of Tables respectively, or by geometric scaling of said coordinates. 
     
     
         19 . The turbomachine of  claim 17  wherein part-span shrouds on respective pressure and suction sides of adjacent ones of said blades at least partially engage along adjacent, substantially straight or Z-shaped contact surfaces. 
     
     
         20 . The turbomachine of  claim 17  wherein said part-span shroud is located substantially midway along said radial height of said airfoil portion.