Theory on the Secondary Flows through Cascades

Abstract

The author treats here theoretically the secondary flows occurring in the cases of flows with non-uniform velocity profiles passing through an axial compressor or a turbine cascade. He assumes this non-uniformity small and divides the three-dimensional flows into two parts, that is, the two dimensional fundamental potential flow and the perturbation flow. Starting from the equation of motion, he derives the elementary differential equation of the perturbation velocity potential. After solving this equation, he shows the method to determine the circulation about blades satisfying Kutta's condition at the trailing edges. Numerical solutions are obtained on the assumption of semi-actuator disc and are compared with experimental values, and a fairly good agreement is obtained for impulse cascades but not for nozzle blades.