Axial compressor rotor incorporating non-axisymmetric hub flowpath and splittered blades

1. A compressor apparatus comprising:

an axial flow rotor comprising:

a disk mounted for rotation about a centerline axis, an outer periphery of the disk defining a flowpath surface having a non-axisymmetric surface profile;

an array of airfoil-shaped axial flow compressor blades extending radially outward from the flowpath surface, wherein the array of compressor blades each have a root, a tip, a leading edge, and a trailing edge; and

an array of airfoil-shaped splitter blades alternating with the compressor blades, wherein the array of splitter blades each have a root, a tip, a leading edge, and a trailing edge;

wherein both a chord dimension of each splitter blade of the array of splitter blades at the roots thereof and a span dimension of each splitter blade of the array of splitter blades are less than the corresponding dimension of the compressor blades;

wherein the splitter blade chord is parallel to the compressor blade chord, at the roots thereof,

wherein each of the blades of the array of 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,

wherein the flowpath surface includes a concave scallop between adjacent compressor blades,

wherein each splitter blade of the array of splitter blades is circumferentially aligned with a deepest portion of the concave scallop,

wherein the selected stage is the aft-most stage of the compressor, and

wherein a forward-most stage of the compressor is un-splittered.

2. The apparatus of claim 1 wherein the flowpath surface includes a concave scallop between adjacent compressor blades.

3. The apparatus of claim 2 wherein the concave 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.

4. The apparatus of claim 1 wherein each splitter blade of the array of splitter blades is located approximately midway between two adjacent compressor blades.

5. The apparatus of claim 1 wherein the span dimension of each splitter blade of the array of splitter blades is 50% or less of the span dimension of the compressor blades.

6. The apparatus of claim 1 wherein the span dimension of each splitter blade of the array of splitter blades is 30% or less of the span dimension of the compressor blades.

7. The apparatus of claim 6 wherein the chord dimension of each splitter blade of the array of splitter blades at the roots thereof is 50% or less of the chord dimension of the compressor blades at the roots thereof.

8. The apparatus of claim 1 wherein the chord dimension of each splitter blade of the array of splitter blades at the roots thereof is 50% or less of the chord dimension of the compressor blades at the roots thereof.

9. A compressor apparatus including a plurality of axial-flow stages, at least a selected one of the stages comprising:

a disk mounted for rotation about a centerline axis, an outer periphery of the disk defining a flowpath surface having a non-axisymmetric surface profile;

an array of airfoil-shaped axial flow compressor blades extending radially outward from the flowpath surface, wherein the array of compressor blades each have a root, a tip, a leading edge, and a trailing edge; and

an array of airfoil-shaped splitter blades alternating with the compressor blades, wherein the array of splitter blades each have a root, a tip, a leading edge, and a trailing edge;

wherein both a chord dimension of each splitter blade of the array of splitter blades at the roots thereof and a span dimension of each splitter blade of the array of splitter blades are less than the corresponding dimension of the compressor blades;

wherein the splitter blade chord is parallel to the compressor blade chord, at the roots thereof,

wherein the array of 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,

wherein the flowpath surface includes a concave scallop between adjacent compressor blades,

wherein each splitter blade of the array of splitter blades is circumferentially aligned with a deepest portion of the concave scallop,

wherein the selected stage is the aft-most stage of the compressor, and

wherein a forward-most stage of the compressor is un-splittered.

10. The apparatus of claim 9 wherein the concave 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.

11. The apparatus of claim 9 wherein each splitter blade of the array of splitter blades is located approximately midway between two adjacent compressor blades.

12. The apparatus of claim 11 wherein the span dimension of each splitter blade of the array of splitter blades is 50% or less of the span dimension of the array of compressor blades; and

wherein the length of the chord of each splitter blade of the array of splitter blade decreases in the radial direction along the splitter blade span.

13. The apparatus of claim 12 wherein the span dimension of each splitter blade of the array of splitter blades is 30% or less of the span dimension of the compressor blades.

14. The apparatus of claim 13 wherein the chord dimension of each splitter blade of the array of splitter blades at the roots thereof is 50% or less of the chord dimension of the compressor blades at the roots thereof.

15. The apparatus of claim 9 wherein the chord dimension of each splitter blade of the array of splitter blades at the roots thereof is 50% or less of the chord dimension of the compressor blades at the roots thereof.