Vortex Prediction in a Pump Intake System Using Computational Fluid Dynamics

A pump intake system consists of forebay, pumpbay and pipeline arrangements through which water flows in order to meet its demand. Vortices and velocity fluctuations affects the performance of a pump intake system. This paper presents the vortex prediction in a pump sump for varying flow conditions across the pump bay and the bellmouth section, using computational fluid dynamics (CFD) code Flow 3D. Geometry of rectangular type sump was chosen for comparing the physical experimentation with the computational model. The velocity fluctuations, location of vortex formation and its profiles predicted by CFD code was compared with that of the physically observed experiments. The velocity and fluid flow profiles predicted by CFD correlated well with the flow conditions observed during the physical experiments. Further, characteristics of vortex were also studied with respect to the velocity change. Increase in the wobbling phenomenon of the vortex with increase in the flow velocity was also identified with the computational studies. CFD can be used as a tool to study the preliminary design of a hydraulic system for a particular field condition, thus complementing the physical model studies to facilitate the construction of an optimized and effective pump intake system.