On the Characteristics of Mixed-Flow Propeller Pumps

Abstract

In order to obtain the characteristic equation of mixed-flow propeller pumps, input headcapacity and hydraulic losses curves are investigated on the basis of experimental results by using various impellers and diffusion casings of different kinds and shapes. Both curves may be represented by flow conditions on the mean flow path, and hydraulic losses in impellers and diffusion vanes may be separated respectively into two parts, one being the friction or diffusion loss and the other shock loss. Each loss-capacity equation and loss coefficient are introduced. Using these relations, the overall characteristic equation for a mixed-flow propeller pump with an open impeller is obtained. It is seen that the agreement between measured and calculated characteristics by this equation is good except in the backflow region in the impeller. The distribution of each hydraulic loss based on this equation is also discussed.