Studies on Circular Cascades for Return Channels of Centrifugal Turbomachinery : 1st Report, Inverse Method and Cascade Design

Abstract

An inverse method to design a circular cascade for a return channel of a centrifugal turbomachine, whose vane-height varies in the radial direction, was developed using the singularity method. As the vane with a round trailing edge was treated in this study, a reasonable position of the rear stagnation point was decided experimentally when a secondary flow occurs considerably on the end walls and a small separation appears on the vane surface. A desirable circular cascade for the return channel, which has a reasonable pressure distribution on the vane surface and satisfies the radial outflow condition, was designed by the developed inverse method in this report.