Compressor impellers

Abstract

An impeller includes a hub having a direction of rotation, a plurality of impeller blades extending from the hub, each blade having a downstream end, an upstream end, a leading surface facing the direction of rotation of the hub, and a trailing surface facing opposite to the direction of rotation of the hub. The impeller further includes a secondary flow reducer extending towards the downstream end and the upstream end of the at least one of the plurality of impeller blades, the secondary flow reducer defining first and second surfaces intersecting one of the leading surface and the trailing surface of the at least one of the plurality of impeller blades as well as a third surface between the first and second surfaces.

What is claimed is: 
     
         1 . An impeller comprising:
 a hub having a direction of rotation;   a plurality of impeller blades extending from said hub, each said blade having a downstream end, an upstream end, a leading surface facing said direction of rotation of said hub, and a trailing surface facing opposite to said direction of rotation of said hub; and   a secondary flow reducer extending towards said downstream end and said upstream end of said at least one of said plurality of impeller blades, said secondary flow reducer defining a first surface and a second surface intersecting one of said leading surface and said trailing surface of said at least one of said plurality of impeller blades and a third surface between said first and second surfaces.   
     
     
         2 . The impeller of  claim 1 , further comprising at least one of the plurality of impeller blades with at least one secondary flow reducer on said leading surface and said trailing surface, the flow reducer being designed following an ideal streamline. 
     
     
         3 . The impeller of  claim 2 , wherein said ideal streamline is substantially parallel to lines associated with the endwalls of the at least one of the impeller blades. 
     
     
         4 . The impeller of  claim 1 , wherein said first surface and said second surface intersect said trailing surface of said at least one impeller blade and extend opposite to said direction of rotation of said hub to said third surface thereby forming a rib on said trailing surface. 
     
     
         5 . The impeller of  claim 1 , wherein said at least one secondary flow reducer comprises a plurality of secondary flow reducers on said trailing surface. 
     
     
         6 . The impeller of  claim 5 , wherein said third surface of each said plurality of secondary flow reducers is congruent to said trailing surface thereby preserving an overall shape of said at least one of said plurality of impeller blades. 
     
     
         7 . The impeller of  claim 5 , wherein said plurality of secondary flow reducers is evenly distributed across said trailing surface. 
     
     
         8 . The impeller of  claim 6 , wherein, for each of said plurality of secondary flow reducers, a curvilinear line defined by said intersection of said first surface with said trailing surface is congruent to a curvilinear line defined by said intersection of said second surface with said trailing surface. 
     
     
         9 . A turbo machine comprising:
 a rotor assembly including at least one impeller of  claim 1 ;   a bearing connected to, and for supporting the rotor assembly; and   a stator.   
     
     
         10 . A turbo machine comprising:
 a rotor assembly including at least one impeller;   a bearing connected to, and for rotatably supporting, the rotor assembly; and   a stator,   wherein said at least one impeller includes:   a hub having a plurality of impeller blades; and   a plurality of ribs on at least one of said plurality of impeller blades for reducing a secondary flow proximate to said at least one impeller blade.   
     
     
         11 . A method of configuring an impeller blade surface to provide reduced secondary flow, said method comprising:
 identifying an ideal streamline of said impeller blade surface; and,   adding a rib to said blade surface coincident with said streamline, said rib defining first and second surfaces intersecting said blade surface and a third surface between said first and second surfaces.   
     
     
         12 . The impeller of  claim 6 , wherein said plurality of secondary flow reducers is evenly distributed across said trailing surface. 
     
     
         13 . The impeller of  claim 2 , wherein said first surface and said second surface intersect said trailing surface of said at least one impeller blade and extend opposite to said direction of rotation of said hub to said third surface thereby forming a rib on said trailing surface. 
     
     
         14 . The impeller of  claim 3 , wherein said first surface and said second surface intersect said trailing surface of said at least one impeller blade and extend opposite to said direction of rotation of said hub to said third surface thereby forming a rib on said trailing surface. 
     
     
         15 . The impeller of  claim 2 , wherein said at least one secondary flow reducer comprises a plurality of secondary flow reducers on said trailing surface. 
     
     
         16 . The impeller of  claim 3 , wherein said at least one secondary flow reducer comprises a plurality of secondary flow reducers on said trailing surface. 
     
     
         17 . The impeller of  claim 4 , wherein said at least one secondary flow reducer comprises a plurality of secondary flow reducers on said trailing surface.