Film cooled turbine component

Abstract

Film cooling of turbine component surfaces, such as high-lift airfoil surfaces, is achieved by a flow of cooling air through film cooling holes of generally constant cross-sectional area, which extend from the surfaces to a radial cooling passage within the airfoil. The film cooling holes are angularly offset from that portion of the radial cooling passage immediately upstream of the film cooling holes by an acute angle which effects a radial reversal of the flow of cooling air into the film cooling holes from the radial cooling passage to reduce the momentum of airflow through the film cooling holes to reduce separation of cooling air film from the surface.

Having thus described the invention, what is claimed is: 
     
         1 . An air-cooled turbine component comprising:
 an outer surface adapted to be cooled by a film of cooling air flowing thereover;   a radial cooling air passage extending through the interior of said component; and   a plurality of film cooling holes extending between said outer surface and said radial cooling passage;   each of said film cooling holes having a substantially constant cross-sectional area along the length thereof;   each of said film cooling holes intersecting said radial cooling passage such that said film cooling hole and that portion of said radial cooling passage immediately upstream from said intersection thereof with said film cooling hole defining an acute angle, whereby cooling air entering said film cooling hole from said radial cooling passage is angularly displaced greater than 90° from the flow of cooling air through said radial cooling passage for decreasing the momentum of airflow through said film cooling hole and any tendency of cooling air discharged from said film cooling hole at said outer airfoil surface to separate therefrom.   
     
     
         2 . The air-cooled turbine airfoil of  claim 1  wherein said acute angle is approximately 25°. 
     
     
         3 . The air-cooled turbine airfoil of  claim 1 , wherein said turbine component comprises a rotor blade. 
     
     
         4 . The air-cooled turbine airfoil of  claim 3 , wherein said surface comprises a concave airfoil pressure surface. 
     
     
         5 . The air-cooled turbine airfoil of  claim 3 , wherein said airfoil surface comprises a convex suction surface. 
     
     
         6 . The air-cooled turbine airfoil of  claim 3 , wherein said surface is an airfoil surface of a shape wherein under normal operation conditions, working fluid flow over said airfoil surface has a ratio of static pressure to total pressure greater than approximately 0.9 over a substantial portion of the entire airfoil surface. 
     
     
         7 . The air-cooled turbine component of  claim 1 , wherein said turbine airfoil comprises a stator vane. 
     
     
         8 . The air-cooled turbine airfoil of  claim 7 , wherein said surface is an airfoil surface of a shape wherein under normal operating conditions, working fluid flow over said airfoil surface has a ratio of static pressure to total pressure greater than approximately 0.9 over a substantial portion of the entire airfoil surface. 
     
     
         9 . An air-cooled turbine component having an outer airfoil surface of an airfoil shape wherein under normal operating conditions, working fluid flow over said airfoil surface has a ratio of static pressure to total pressure greater than approximately 0.9 over a substantial portion of the entire airfoil surface, said air-cooled turbine component comprising:
 a radial cooling passage defined by a continuous sidewall extending through the interior of said airfoil; and   at least one film cooling hole defined by a continuous sidewall and extending between said outer airfoil surface and said radial cooling passage;   said film cooling hole having a substantially constant cross-sectional area along the length thereof;   said turbine component further comprising a flow diverter at the intersection of said film cooling hole and said radial cooling passage for the substantial reversal of the radial component of cooling air flow into said film cooling hole from cooling airflow through said radial cooling passage.   
     
     
         10 . The air-cooled turbine component of  claim 9 , wherein said flow diverter comprises an intersection of the sidewalls of said film cooling hole and said radial cooling passage. 
     
     
         11 . The air-cooled turbine component of  claim 10 , wherein said flow diverter angularly displaces the flow of cooling air entering said film cooling hole from said radial cooling passage substantially between 90° and 180°. 
     
     
         12 . The air-cooled turbine component of  claim 11 , wherein said turbine component comprises a rotor blade. 
     
     
         13 . The air-cooled turbine component of  claim 12 , wherein said airfoil surface comprises a concave pressure surface. 
     
     
         14 . The air-cooled turbine component of  claim 12 , wherein said airfoil surface comprises a convex suction surface. 
     
     
         15 . The air-cooled turbine component of  claim 11 , wherein said turbine component comprises a stator vane.