2427 Unsteady Flow in Pump Sump

Abstract

Numerical calculations were carried out on unsteady flows in a pump sump with a cylindrical suction pipe using a commercial CFD code (CFX-10.0) in order to investigate the mechanism of the air-entraining vortex generation. The calculated results show that the dimple generated behind a suction pipe moves to the downstream with growing up, and the air-entraining vortices generated when the dimple reaches the vortex from a suction pipe. The calculated geometry of water surface in a pump sump near a suction pipe was compared with one measured by moire method. The dimple on the surface behind the suction pipe was found to grow up to the air-entraining vortex. The measured and calculated results agree well. As a result of the present study, it was found that mechanism of the entraining-vortex generation can be captured by CFD.