Controlled flow turbine blades

Abstract

The present application provides a turbine blade. The turbine blade includes a root section with a first curved section, a tip section with a second curved section, and number of mean sections positioned between the root section and the tip section. The mean sections each include a substantially prismatic shape.

We claim: 
     
         1 . A turbine blade, comprising:
 a root section;   the root section comprising a first curved section;   a tip section;   the tip section comprising a second curved section; and   a plurality of mean sections positioned between the root section and the tip section;   the plurality of mean sections each comprising a substantially prismatic shape.   
     
     
         2 . The turbine blade of  claim 1 , wherein the substantially prismatic shape comprises a ratio (K) of a throat dimension to a pitch dimension of K±0.1. 
     
     
         3 . The turbine blade of  claim 1 , wherein the plurality of mean sections comprises a reduced axial width as compared to the first curved section and the second curved section. 
     
     
         4 . The turbine blade of  claim 1 , wherein the first curved section and the second curved section comprise an inward curve away from the plurality of mean sections. 
     
     
         5 . The turbine blade of  claim 1 , wherein the first curved section comprises a first decreasing blade outlet angle, wherein the second curved section comprises a second decreasing blade outlet angle, and wherein the plurality of mean sections comprises a substantially constant blade outlet angle. 
     
     
         6 . The turbine blade of  claim 5 , wherein the first decreasing blade outlet angle and the second decreasing blade outlet angle are less than the substantially constant blade outlet angle. 
     
     
         7 . The turbine blade of  claim 5 , wherein the first decreasing blade outlet angle and the second decreasing blade outlet angle are between about two and eight degrees. 
     
     
         8 . The turbine blade of  claim 1 , wherein the first curved section comprises a first ratio of a throat dimension to a pitch dimension, wherein the second curved section comprises a second ratio, and wherein the plurality of mean sections comprises a substantially constant ratio. 
     
     
         9 . The turbine blade of  claim 8 , wherein the first ratio and the curved ratio are less than the substantially constant ratio. 
     
     
         10 . The turbine blade of  claim 8 , wherein a first change in the first ratio along the first curved section and a second change in the second ratio along the second curved section are greater than a mean change in the substantially constant ratio ±0.1 along the plurality of mean sections. 
     
     
         11 . The turbine blade of  claim 1 , wherein the first curved section extends along a first height of the blade from about zero percent to about fifty percent of a total height of the blade for an aspect ratio of about one to two. 
     
     
         12 . The turbine blade of  claim 1 , wherein the second curved section extends along a second height of the blade from about fifty percent to about one hundred percent of a total height of the blade for an aspect ratio of about one to two. 
     
     
         13 . The turbine blade of  claim 1 , wherein the first curved section extends along a first height of the blade from about zero percent to about fifteen percent of a total height of the blade for an aspect ratio of higher than about two. 
     
     
         14 . The turbine blade of  claim 1 , wherein the second curved section extends along a second height of the blade from about eighty-five percent to about  100  percent of a total height of the blade for an aspect ratio of higher than about two. 
     
     
         15 . The turbine blade of  claim 1 , comprising an aspect ratio of about one to six. 
     
     
         16 . A steam turbine blade, comprising:
 a root section;   the root section comprising a first curved section;   a tip section;   the tip section comprising a second curved section; and   a plurality of mean sections positioned between the root section and the tip section;   the plurality of mean sections comprises a substantially prismatic shape and a reduced axial width as compared to the first curved section and the second curved section.   
     
     
         17 . The steam turbine blade of  claim 16 , wherein the substantially prismatic shape comprises a ratio (K) of a throat dimension to a pitch dimension of K±0.1. 
     
     
         18 . The steam turbine blade of  claim 16 , wherein the first curved section comprises a first decreasing blade outlet angle, wherein the second curved section comprises a second decreasing blade outlet angle, wherein the plurality of mean sections comprises a substantially constant blade outlet angle, and wherein the first decreasing blade outlet angle and the second decreasing blade outlet angle are less than the substantially constant blade outlet angle. 
     
     
         19 . The steam turbine blade of  claim 18 , wherein the first decreasing blade outlet angle (α) and the second decreasing blade outlet angle (α) are between about two and eight degrees. 
     
     
         20 . The steam turbine blade of  claim 16 , comprising an aspect ratio of about one to six.