Blades with decreasing exit flow angle

Abstract

An axial rotor includes a plurality of blades extending from a hub that is rotatable about an axis of rotation. Each of the plurality of blades includes a blade body that extends over a span from a base to a tip. The plurality of blades defines an exit flow angle relative to a plane that is perpendicular to the axis of rotation. The exit flow angle decreases along the span from the base to the tip.

1 . An axial rotor comprising:
 a plurality of blades extending from a hub and arranged about an axis, each of the plurality of blades including a blade body extending over a span from a base to a tip, the plurality of blades defining an exit flow angle relative to a plane that is perpendicular to the axis of rotation, the exit flow angle decreasing along the span from the base to the tip.   
     
     
         2 . The axial rotor as recited in  claim 1 , wherein an average exit flow angle over the span is less than 12°. 
     
     
         3 . The axial rotor as recited in  claim 1 , wherein a proportional ratio of a maximum exit flow angle along the span to a minimum exit flow angle along the span is no greater than 2.33. 
     
     
         4 . The axial rotor as recited in  claim 1 , wherein the rate of decrease of the exit flow angle along the span from the base to the tip is non-linear. 
     
     
         5 . The axial rotor as recited in  claim 1 , wherein the exit flow angle at the tip is 5-12° and the exit flow angle at the base is 12-20°. 
     
     
         6 . The axial rotor as recited in  claim 1 , wherein a proportional ratio of a maximum exit flow angle at the base and a minimum exit flow angle at the tip is greater than 1 and less than or equal to 4. 
     
     
         7 . The axial rotor as recited in  claim 1 , wherein the blade body extends between a leading edge and a trailing edge and a suction side surface and a pressure side surface, the suction side surface and the pressure side surface being defined by a set of coordinates and a radii of curvature at each coordinate as set forth in Table I and scaled by a desirable factor. 
     
     
         8 . The axial rotor of  claim 1 , wherein under normal operating conditions, a fluid flow about each of the plurality of blades does not separate near the trailing edge near the hub and wherein the fluid flow about each of the plurality of blades does not separate near the trailing edge near the tip. 
     
     
         9 . A turbopump machine comprising:
 a rotatable shaft;   a pump coupled to rotate with the rotatable shaft;   a turbine coupled to drive the rotatable shaft, the turbine including an axial rotor having a plurality of blades extending from a hub that is rotatable about an axis of rotation, each of the plurality of blades including a blade body extending over a span from a base to a tip, the plurality of blades defining an exit flow angle relative to a plane that is perpendicular to the axis of rotation, the exit flow angle decreasing along the span from the base to the tip.   
     
     
         10 . A method of controlling flow over an axial rotor, the method comprising:
 for an axial rotor that includes a plurality of blades extending from a hub that is rotatable about an axis of rotation, each of the plurality of blades including a blade body extending over a span from a base to a tip, the plurality of blades defining an exit flow angle relative to a plane that is perpendicular to the axis of rotation, establishing a decreasing exit flow angle along the span from the base to the tip.   
     
     
         11 . The method as recited in  claim 9 , including establishing an average exit flow angle of less than 12° over the span from the base to the tip. 
     
     
         12 . The method as recited in  claim 9 , including establishing a proportional ratio of a maximum exit flow angle along the span to a minimum exit flow angle along the span that is no greater than 2.33. 
     
     
         13 . The method as recited in  claim 9 , including establishing the rate of decrease of the exit flow angle along the span from the base to the tip to be non-linear. 
     
     
         14 . The method as recited in  claim 9 , including establishing the exit flow angle at the tip to be 5-12° and the exit flow angle at the base to be 12-20°. 
     
     
         15 . The method as recited in  claim 9 , including establishing a proportional ratio of a maximum exit flow angle along the span at the base and a minimum exit flow angle at the tip to be greater than 1 and less than or equal to 4. 
     
     
         16 . The method as recited in  claim 9 , wherein the blade body extends between a leading edge and a trailing edge and a suction side surface and a pressure side surface, the suction side surface and the pressure side surface being defined by a set of coordinates and a radius of curvature at each coordinate as set forth in Table I and scaled by a desirable factor. 
     
     
         17 . The method as recited in  claim 9 , including operating the axial rotor at a speed of 3500-4500 revolutions per minute to drive a pump that coupled with the axial rotor at the same speed. 
     
     
         18 . An axial turbine comprising:
 a plurality of airfoils that extend from a hub, each of the plurality of airfoils including an airfoil body extending between a leading end, a trailing end, a base at the hub, and a tip and defining a mean camber line, wherein a camber angle of the mean camber line at the trailing end relative to a plane that is perpendicular to an axis about which the plurality of airfoils are arranged is between approximately 5° and approximately 12° near the tip and is between approximately 12° and approximately 20° near the hub.   
     
     
         19 . The axial turbine of  claim 18 , wherein under normal operating conditions, a fluid flow about each of the plurality of airfoils does not separate near the trailing edge near the hub and wherein the fluid flow about each of the plurality of airfoils does not separate near the trailing edge near the tip.