Numerical investigation of vortex formation in water intake system of a pumping station during low and high tides

Abstract

AbstractThe performance of pumps installed in pumping stations depends greatly on vortex formation at pipe intakes. Using numerical simulations and experimental methods, this study focuses on vortex formation in water intake system of a pumping station under the tidal conditions of the Bahmanshir River. The intake system consisted of a suction pipe and a fine intake screen. Realizable k–ε turbulence model together with volume of fluid (VOF) two-phase (water–air) model are used to simulate the flow field in the water intake system. Vortex formation, flow pattern and flow uniformity are investigated. Water levels and free surface velocities of the river are measured in a 1-year period. The water levels range from 2.1 to 4.9 m and the corresponding free surface velocity varies from 1.05 to 2.35 m/s. The numerical results show that two wall-attached vortices permanently stretched to the intake screen. Additionally, two symmetrical vortices with different intensities formed in the intake screen. As the submergence of the intake pipe decreases during low tides, stronger vortices arise in the screen. Analysis of the velocity uniformity shows low level of flow uniformity at the pump intake. Low level of uniformity is attributed to the existence of the intake screen and its check valve, which facilitates the formation of vortices in the suction pipe. Based on present analysis, recommendations for modifications and improvements to the design of the pumping station are presented.