The flows within a pump station is unstable turbulent flows in reality, therefore a turbulent, transient multiphase flow solver was chosen for the CFD analysis. The interFoam RAS turbulence model (komega-SST) was chosen for the numerical simulation.Inflow consists of velocity fixed velocity values while the outlet was modelled also using the fixed velocity function. Pre-rotation induced by the by the pump’s propeller does not affect upstream flow patterns when the pump is operated at design flow and hence including propeller in the numerical modelis not required.Simulation scenarios was described at left table.