Compressor incorporating splitters

Abstract

A compressor apparatus includes: an inner flowpath surface; an outer flowpath surface; an array of stator airfoils extending between the inner and outer flowpath surfaces; and an array of airfoil-shaped splitter vanes extending from at least one of the inner and outer flowpath surfaces, the splitter vanes alternating with the stator airfoils, wherein at least one of a chord dimension of the splitter vanes at the roots thereof and a span dimension of the splitter vanes is less than a corresponding dimension of the stator airfoils.

What is claimed is: 
     
         1 . A compressor apparatus comprising:
 an arcuate inner wall defining an inner flowpath surface;   an arcuate outer wall defining an outer flowpath surface;   an array of axial-flow stator airfoils extending between the inner and outer flowpath surfaces, wherein the stator airfoils each have a root, a tip, a leading edge, and a trailing edge, wherein the stator airfoils have a chord dimension and are spaced apart by a circumferential spacing, the ratio of the chord dimension to the circumferential spacing defining a stator airfoil solidity parameter; and   an array of airfoil-shaped splitter vanes extending from at least one of the inner and outer flowpath surfaces, the splitter vanes alternating with the stator airfoils, wherein the splitter vanes each have a root, a tip, a leading edge, and a trailing edge;   wherein at least one of a chord dimension of the splitter vanes at the roots thereof and a span dimension of the splitter vanes is less than the corresponding dimension of the stator airfoils.   
     
     
         2 . The apparatus of  claim 1  wherein the splitter vanes extend from both the inner and outer flowpath surfaces. 
     
     
         3 . The apparatus of  claim 1  wherein the stator airfoil solidity parameter is selected to as to result in flow separation under normal operating conditions. 
     
     
         4 . The apparatus of  claim 1  wherein at least one of the inner and outer flowpath surfaces is not a body of revolution. 
     
     
         5 . The apparatus of  claim 1  wherein each of the splitter vanes is located approximately midway between two adjacent stator airfoils. 
     
     
         6 . The apparatus of  claim 1  wherein the splitter vanes are positioned such that their trailing edges are at approximately the same axial position as the trailing edges of the stator airfoils, relative to the inner and outer flowpath surfaces. 
     
     
         7 . The apparatus of  claim 1  wherein the span dimension of the splitter vanes is 50% or less of the span dimension of the stator airfoils. 
     
     
         8 . The apparatus of  claim 1  wherein the span dimension of the splitter vanes is 30% or less of the span dimension of the stator airfoils. 
     
     
         9 . The apparatus of  claim 8  wherein the chord dimension of the splitter vanes at the roots thereof is 50% or less of the chord dimension of the stator airfoils at the roots thereof. 
     
     
         10 . The apparatus of  claim 1  wherein the chord dimension of the splitter vanes at the roots thereof is 50% or less of the chord dimension of the stator airfoils at the roots thereof. 
     
     
         11 . A compressor apparatus comprising:
 a rotor comprising:
 a disk mounted for rotation about a centerline axis, an outer periphery of the disk defining a rotor flowpath surface; 
 an array of airfoil-shaped axial-flow compressor blades extending radially outward from the rotor flowpath surface, wherein the compressor blades each have a root, a tip, a leading edge, and a trailing edge, wherein the compressor blades have a chord dimension and are spaced apart by a circumferential spacing, the ratio of the chord dimension to the circumferential spacing defining a blade solidity parameter; 
   an array of airfoil-shaped splitter blades alternating with the compressor blades, wherein the splitter blades each have a root, a tip, a leading edge, and a trailing edge;   wherein at least one of a chord dimension of the splitter blades at the roots thereof and a span dimension of the splitter blades is less than the corresponding dimension of the compressor blades;   a stator comprising:
 an arcuate inner wall defining an inner flowpath surface; 
 an arcuate outer wall defining an outer flowpath surface; 
 an array of axial-flow stator airfoils extending between the inner and outer flowpath surfaces, wherein the stator airfoils each have a root, a tip, a leading edge, and a trailing edge, wherein the stator airfoils have a chord dimension and are spaced apart by a circumferential spacing, the ratio of the chord dimension to the circumferential spacing defining a stator airfoil solidity parameter; and 
 an array of airfoil-shaped splitter vanes extending from at least one of the inner and outer flowpath surfaces, the splitter vanes alternating with the stator airfoils, wherein the splitter vanes each have a root, a tip, a leading edge, and a trailing edge; 
 wherein at least one of a chord dimension of the splitter vanes at the roots thereof and a span dimension of the splitter vanes is less than the corresponding dimension of the stator airfoils. 
   
     
     
         12 . The apparatus of  claim 11  wherein the blade solidity parameter is selected to as to result in hub flow separation under normal operating conditions. 
     
     
         13 . The apparatus of  claim 11  wherein the rotor flowpath surface is not a body of revolution. 
     
     
         14 . The apparatus of  claim 11  wherein the rotor flowpath surface includes a concave scallop between adjacent compressor blades. 
     
     
         15 . The apparatus of  claim 14  wherein the scallop has a minimum radial depth adjacent the roots of the compressor blades, and has a maximum radial depth at a position approximately midway between adjacent compressor blades. 
     
     
         16 . The apparatus of  claim 11  wherein each splitter blade is located approximately midway between two adjacent compressor blades. 
     
     
         17 . The apparatus of  claim 11  wherein the splitter blades are positioned such that their trailing edges are at approximately the same axial position as the trailing edges of the compressor blades, relative to the disk. 
     
     
         18 . The apparatus of  claim 11  wherein the span dimension of the splitter blades is 50% or less of the span dimension of the compressor blades. 
     
     
         19 . The apparatus of  claim 11  wherein the span dimension of the splitter blades is 30% or less of the span dimension of the compressor blades. 
     
     
         20 . The apparatus of  claim 19  wherein the chord dimension of the splitter blades at the roots thereof is 50% or less of the chord dimension of the compressor blades at the roots thereof. 
     
     
         21 . The apparatus of  claim 11  wherein the chord dimension of the splitter blades at the roots thereof is 50% or less of the chord dimension of the compressor blades at the roots thereof.