Three-dimensional inviscid effects in axial flow turbomachinery and limitation of cascade theory

The calculation was based on the method of distributed singularities; the blades are represented by a series of line vortices and line sources which have their axes along the radial direction and are arranged along the blade camber surface. The basic perturbed velocity fields due to radial vortex lines of constant strength and radial source lines of variable strength were computed from a modified theory based on Tyson's and Rossow's formulation. A computer program was developed to obtain the three dimensional flow field in a turbomachinery with arbitrary number of blades, number of singular points per blade, and various hub/tip ratios. Examples are presented illustrating the three dimensional effects due to hub/tip ratio, stagger angle, number of the blades. The effects of the radial variation of the strength of the radial source line were examined. The three dimensional effects are found to be appreciable for low hub/tip configuration with fewer number of blades.