Effects of Inlet Velocity Distribution on Cavitation Surge in a Conical Diffuser

Abstract

By a theoretical study with an one-dimensional model and an experimental investigation with conical diffusers, it has been found that the diffuser effect of the draft tube cause cavitation surge. The present study focuses on effects of the swirl inflow and its velocity distribution at the inlet of the diffuser. Experimental and numerical investigations are carried out with a conical diffuser and a two-stage swirler at the inlet. Results show that the inlet circumferential velocity distribution affects the wall pressure distribution, and finally occurrence of the cavitation surge.