Modeling Flow Phenomena in Pump Station with Overflow

Abstract

This paper deals with the numerical analysis of flow in a complete hydraulic system representing the pump station including the influence of the free water level. Particular attention is paid to the discharge object with overflow, which is characterized by the critical flow across the crown of the overflow wall. All basic calculations were accomplished by means of the commercial software ANSYS CFX and ANSYS Fluent with the SST turbulence model. As the flow in the discharge object represents the most interesting part of the results, additional numerical simulations of flow just inside this object were carried out with the DDES scale resolving simulations. Basic calculations inside the complete pump station passage gave surprisingly steady water level in both the intake and discharge objects. They also provided a good picture of the distribution of water velocity close to the water level and corresponding height of water level above the overflow wall crown. DDES simulations indicated a periodically formed vortex on a water level behind the overflow wall crown, with a (not very distinct) Strouhal number about 0.3.