Undercut leading edge for compressor blades and related method

Abstract

A compressor blade includes an airfoil portion having a leading edge, a radially inner attachment portion, and a platform between the airfoil portion and the attachment portion, wherein material is removed from the attachment portion to form an undercut at a front face thereof to thereby provide an overhang radially inward of the platform and leading edge of the airfoil portion, the undercut defined by a narrow entry slot opening into a rearward transverse groove.

1 . A compressor blade comprising an airfoil portion having a leading edge, a radially inner attachment portion, and a platform between the airfoil portion and the attachment portion, wherein material is removed from the attachment portion to form an undercut at a front face thereof to thereby provide an overhang radially inward of the platform and leading edge of the airfoil portion, the undercut defined by a narrow transverse entry slot opening into a rearward transverse groove.  
     
     
         2 . The compressor blade of  claim 1  wherein, when assembled on a compressor wheel, a void created by the undercut is filled by an acoustic damper having substantially the same shape as the void.  
     
     
         3 . The compressor blade of  claim 2  wherein said acoustic damper is constructed of a high strength plastic material.  
     
     
         4 . The compressor blade of  claim 3  wherein said acoustic damper is constructed of nylon.  
     
     
         5 . The compressor blade of  claim 1  wherein said groove is round and has a diameter of about 0.5 inch.  
     
     
         6 . The compressor blade of  claim 1  wherein the undercut extends in an axial direction at least to the leading edge of the airfoil portion.  
     
     
         7 . A compressor blade comprising an airfoil portion having a leading edge, a radially inner attachment portion, and a platform between the airfoil portion and the attachment portion, wherein material is removed from the attachment portion to form an undercut in a front face thereof at least and including a transverse, substantially round groove rearward of said front face to thereby provide an overhang radially inward of the platform and leading edge of the airfoil portion; wherein, when assembled on a compressor wheel, a void space created by the undercut is substantially filled by an acoustic damper.  
     
     
         8 . The compressor blade of  claim 7  wherein said acoustic damper is constructed of a high strength plastic material.  
     
     
         9 . The compressor blade of  claim 7  wherein said acoustic damper is constructed of nylon.  
     
     
         10 . The compressor blade of  claim 7  wherein a narrow transverse entry slot opens into said transverse groove, said groove having a diameter of about 0.5 inch.  
     
     
         11 . A method of unloading a leading edge of an airfoil portion of a compressor blade comprising: 
 a) providing the blade having the airfoil portion with the leading edge, a platform, and an attachment portion adapted to secure the blade to a compressor wheel; and    b) removing material from the attachment portion to create an undercut radially inward of the leading edge of the airfoil portion, and defined by a narrow transverse entry slot opening into a rearward transverse groove.    
     
     
         12 . The method of  claim 11  wherein, when assembled on the compressor wheel, a void created by the undercut is filled by an acoustic damper having substantially the same shape as the void.  
     
     
         13 . The method of  claim 12  wherein said acoustic damper comprises a high strength plastic material.  
     
     
         14 . The method of  claim 12  wherein said acoustic damper comprises nylon.  
     
     
         15 . The method of  claim 11  wherein the undercut extends in an axial direction at least to the leading edge of the airfoil portion.  
     
     
         16 . The method of  claim 11  wherein said rearward transverse groove is substantially round in shape.  
     
     
         17 . The method of  claim 16  wherein said groove has a diameter of about {fraction (1/2)} inch.