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Mathematical Problems in Engineering
Volume 2014, Article ID 735416, 20 pages
http://dx.doi.org/10.1155/2014/735416
Research Article

Numerical and Experimental Study of Pump Sump Flows

1Department of Hydraulic and Ocean Engineering, National Cheng Kung University, Tainan 701, Taiwan
2Tainan Hydraulics Laboratory, National Cheng Kung University, Tainan 701, Taiwan

Received 21 August 2013; Revised 24 January 2014; Accepted 7 February 2014; Published 24 April 2014

Academic Editor: Jian Guo Zhou

Copyright © 2014 Wei-Liang Chuang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The present study analyzes pump sump flows with various discharges and gate submergence. Investigations using a three-dimensional large eddy simulation model and an acoustic Doppler velocimeter are performed. Flow patterns and velocity profiles in the approaching flow are shown to describe the flow features caused by various discharges and gate submergence. The variation of a large-scale spanwise vortex behind a sluice gate is examined and discussed. The suction effect on approaching flow near the pipe column is examined using numerical modeling. To gain more understanding of the vortices variation, a comparison between time-averaged and instantaneous flow patterns is numerically conducted. Additionally, swirl angle, a widely used index for evaluating pump efficiency, is experimentally and numerically examined under various flow conditions. The results indicate that the pump becomes less efficient with increasing discharge and gate submergence. The fluctuation of the free surface over the pump sump is also discussed.