Axial fan blade with wavy airfoil and trailing edge serrations

Abstract

An axial flow fan includes a hub rotatable about a fan axis and a plurality of fan blades mounted to the hub. One of the plurality of fan blades includes at least one wave extending in a span wise direction over the fan blade and at least one serration extending along a trailing edge of the fan blade. The at least one wave and the at least one serration are arranged at a location between 40% and 100% of a span of the fan blade.

1 . An axial flow fan comprising:
 a hub rotatable about a fan axis;   a plurality of fan blades mounted to the hub, wherein one of the plurality of fan blades includes at least one wave extending in a span wise direction over the fan blade and at least one serration extending along a trailing edge of the fan blade, wherein the at least one wave and the at least one serration are arranged at a location between 40% and 100% of a span of the fan blade.   
     
     
         2 . The axial flow fan of  claim 1 , wherein the at least one wave is positioned adjacent a trailing edge of the fan blade. 
     
     
         3 . The axial flow fan of  claim 2 , wherein the at least one wave is arranged between 30%-100% of the chord as measured from a leading edge of the fan blade. 
     
     
         4 . The axial flow fan of  claim 1 , wherein the at least one serration is formed in a chord of the fan blade. 
     
     
         5 . The axial flow fan of  claim 1 , wherein a height of the at least one serration has is equal to between 0% and 30% of a chord length of the fan blade. 
     
     
         6 . The axial flow fan of  claim 1 , wherein a contour of the at least one wave is generally smooth. 
     
     
         7 . The axial flow fan of  claim 1 , wherein a contour of the at least one wave is generally sharp. 
     
     
         8 . The axial flow fan of  claim 1 , wherein the at least one wave includes a plurality of waves. 
     
     
         9 . The axial flow fan of  claim 8 , wherein the plurality of waves includes between two waves and six waves. 
     
     
         10 . The axial flow fan of  claim 1 , wherein a contour of the at least one serration is generally smooth. 
     
     
         11 . The axial flow fan of  claim 1 , wherein a contour of the at least one serration is generally sharp. 
     
     
         12 . The axial flow fan of  claim 1 , wherein the at least one serration includes a plurality of serrations. 
     
     
         13 . The axial flow fan of  claim 12 , wherein the plurality of waves includes between two serrations and six serrations. 
     
     
         14 . The axial flow fan of  claim 1 , wherein the at least one wave is equal in number to the at least one serration. 
     
     
         15 . The axial flow fan of  claim 1 , wherein a cross-section of the fan blade has a profiled airfoil shape. 
     
     
         16 . The axial flow fan of  claim 1 , wherein the fan blade has a sweep. 
     
     
         17 . The axial flow fan of  claim 1 , further comprising a shroud coupled to a tip end of each of the plurality of fan blades such that the shroud is rotatable about the fan axis. 
     
     
         18 . The axial flow fan of  claim 1 , wherein the axial flow fan is formed from a plastic material via an injection molding process. 
     
     
         19 . The axial flow fan of  claim 1 , wherein an amplitude of the one or more waves as measured along an axial dimension is larger at the trailing edge than at the leading edge. 
     
     
         20 . The axial flow fan of  claim 1 , wherein an amplitude of the one or more waves as measured along the axial dimension varies continuously from the trailing edge than at the leading edge. 
     
     
         21 . An axial flow fan comprising:
 a hub rotatable about a fan axis;   a plurality of fan blades mounted to the hub; and   a shroud mounted to a tip end of each of the plurality of fan blades;   wherein each of the plurality of fan blades includes three waves extending in a span wise direction over the fan blade, the three waves being positioned adjacent a trailing edge of the fan blade between 40% and 100% of a span of the fan blade; and   wherein each of the plurality of fan blades includes three serrations extending in a chord wise direction over the fan blade, the three serrations being positioned adjacent a trailing edge of the fan blade between 40% and 100% of a span of the fan blade.