Connected Vortex in a Pump Sump with Two Suction Pipes

Abstract

When multiple suction pipes are installed in a pump sump of a drainage pump station, sometimes interaction between pipes generates a strong connected vortex. There are many unclear points about the behavior of such connected vortex, and the influence of parameters such as distance between the suction pipes and flow speed on the generation conditions is unknown. In this study, the behavior of vortices in a pump sump with two vertical suction pipes is reproduced numerically. In some cases, a connected vortex with a vorticity equal to or higher than that of the air-entraining vortex was generated. Also the connected vortex becomes less likely to occur if the distance between the suction pipes is larger, but the flow velocity has some effect on it. The unsteady and periodic vortex shedding influences the flow of connected vortex, and sometimes it changes the direction of rotation of connected vortex in the result of steady simulation. The flow in this type of pump sump has strong unsteadiness, unsteady simulation is necessary to get a reliable result.