Prediction of Air-Entrained Vortex in Pump Sump: Influence of Turbulence Models and Interface-Tracking Methods

An air-entrained vortex is a complicated and negative phenomenon in a pump sump. Due to the unsteady vortical and two-phase-flow properties, its prediction is challenging. In this paper, advanced turbulence models sensitive to rotation and an interface tracking method for complex interfaces were applied to a benchmark pump sump case. For comparison, conventional models or method also were adopted. The performance of these approaches was investigated in detail based on the open-source computational fluid dynamics (CFD) code OpenFOAM. Comparison of various turbulence models revealed that the models which included rotation effects achieved better performance. The air-entrained vortex was found to be a relatively small-scale vortex with large turbulence energy. For the interface tracking, the simplified coupled level set and volume of fluid (S-CLSVOF) method, which combines the volume of fluid and level set methods, was proven to be more appropriate. The air-entrainment rate can be used to judge when the air-entrained vortex occurs during the numerical simulation if S-CLSVOF is used. In general, the advanced methods introduced in this paper are promising in reproducing the air-entrained vortex in pump sump.