Airfoil Having an Improved Trailing Edge

Abstract

An airfoil ( 101 ) is provided which includes a suction side and a pressure side joined along a trailing edge ( 106 ), wherein a trailing edge portion of the airfoil is configured to take a wavelike form along a radial direction of the airfoil, thereby improving the radial bending strength of the airfoil and reducing the magnitude of fluid flow wakes ( 128′ ) formed in a working fluid flowing over the airfoil.

1 . An airfoil comprising:
 a suction side and a pressure side joined along a trailing edge;   wherein a trailing edge portion of the airfoil is configured to take a wavelike form along a radial direction of the airfoil.   
     
     
         2 . The airfoil of  claim 1 , wherein an amplitude of said wavelike form varies from a maximum value at the trailing edge to zero at a predetermined distance along a cord length of the airfoil. 
     
     
         3 . The airfoil of  claim 2 , wherein an amplitude of said wavelike form at said trailing edge is in a range of 0.2-2 times a thickness of the trailing edge. 
     
     
         4 . The airfoil of  claim 3 , wherein said amplitude of said wavelike form at said trailing edge is approximately equal to the thickness of the trailing edge. 
     
     
         5 . The airfoil of  claim 2 , wherein a thickness the airfoil at said predetermined distance is in a range of 2-3 times a thickness of the trailing edge. 
     
     
         6 . The airfoil of  claim 1 , wherein a wavelength of said wavelike form along said trailing edge is in a range of 2-4 times a thickness of the trailing edge. 
     
     
         7 . The airfoil of  claim 1 , wherein the wavelike form comprises a sine wave form. 
     
     
         8 . The airfoil of  claim 1 , wherein the wavelike form comprises a tapered square wave form comprising alternating flat levels having different relative elevations joined by respective sloped sections joining the two levels. 
     
     
         9 . A system comprising:
 a stationary airfoil;   a rotating airfoil positioned downstream from the stationary airfoil in a fluid flow stream;   wherein a trailing edge portion of the stationary airfoil is configured to take a wavelike form along a radial direction of the stationary airfoil effective to enhance a mixture of pressurized fluid from respective suction and pressure sides of the stationary airfoil downstream of the trailing edge and to reduce instances of planar wakes incident from said stationary airfoil onto said rotating airfoil.   
     
     
         10 . The system of  claim 9 , wherein an amplitude of said wavelike form varies from a maximum at the trailing edge to zero at a predetermined distance along a cord length of the airfoil. 
     
     
         11 . The system of  claim 10 , wherein a thickness the stationary airfoil at said predetermined distance is in a range of 2-3 times a thickness of the trailing edge. 
     
     
         12 . The system of  claim 9 , wherein said trailing edge portion of the stationary airfoil comprises a ceramic matrix composite material. 
     
     
         13 . The system of  claim 9 , wherein the wavelike form comprises a sine wave form. 
     
     
         14 . The system of  claim 9 , wherein the wavelike form comprises a tapered square wave form comprising alternating flat levels having different relative elevations joined by respective sloped sections joining the two levels. 
     
     
         15 . A system comprising a row of stationary airfoils upstream of a row of rotating airfoils in a working fluid flow stream, said respective stationary airfoils each comprising a suction side and a pressure side joined along a trailing edge, wherein the improvement comprises a trailing edge portion of each stationary airfoil comprising a wavelike form. 
     
     
         16 . The system of  claim 15 , wherein an amplitude of said respective wavelike forms varies from a maximum at the trailing edge to zero along a chord length of the respective stationary airfoil, and a thickness of the respective stationary airfoil at said predetermined distance is in a range of 2-3 times a thickness of the trailing edge. 
     
     
         17 . The system of  claim 15 , wherein said trailing edge portion of each stationary airfoil comprises a ceramic matrix composite material. 
     
     
         18 . The system of  claim 15 , wherein the wavelike form comprises a sine wave form. 
     
     
         19 . The system of  claim 15 , wherein the wavelike form comprises a tapered square wave form comprising alternating flat levels having different relative elevations joined by respective sloped sections joining the two levels.