EFFECT OF SUMP GEOMETRY AND SUBMERGENCE DEPTH ON FREE SURFACE VORTEX FORMATION OF PUMP INFLOW

Abstract

This paper examines and discusses pump sump design as it affects unsteady pump inflow. It is shown that an improvement of the unsteady inflow characteristics can be accomplished by introducing some modifications to the pump sump design. The paper introduces a 3D numerical computation of unsteady flow through a water sump into the intake of a large vertical pump. The numerical simulation is performed using ANSYS CFX. Numerical simulations performed use the shear stress transport model to account for the effect of turbulence. The results obtained were verified by comparison with published experimental data. The effect of the sump geometry and water level on the internal flow in pump sump is presented. Four sump geometries were studied: a rectangular sump, a sump with inclined edge at 30°, a sump with inclined edge at 45°, and a half-circle-ended sump. Also, three submergence levels were studied: S/D = 1.015, 0.771, and 0.54. It is concluded that sumps of rectangular geometry are the best to avoid surface and floor vortex formation.