Modeling and Optimization of Multiphase Flow in Pump Station

Abstract

This paper presents the numerical analysis of flow in the pumping station including the influence of free water level in the suction and discharge objects. The suction object is based on a draft tube. Two solutions of the discharge objects (with the overflow walls and with the welded siphon) are compared so as to optimize the efficiency and start-up of the station. All calculations are based on the ANSYS CFX software with the SAS-SST and the DES scale resolving simulations. The numerical solution of the free-surface flow is carried out by means of the Volume-of-Fluid method. Calculations of flow inside one complete pump station passage provide a good picture of the distribution of water velocities and the corresponding heights of water level in front of the suction draft tube, above the overflow wall crown as well as inside and behind the siphon during the start-up. The calculations are verified with some experiments carried out in the hydraulic laboratory of the Centre of Hydraulic Research. Conclusions show the higher overall efficiency of the station with the siphon-based discharge objects but also indicate some special requirements for the start-up of this station.