Validation of the steady and unsteady simulation based on an axial-flow pump

Abstract An axial-flow pump offers high flow rates and efficiency with low power consumption, making it ideal for applications that require transferring the large volume of fluid. Applying the numerical simulation in predicting hydraulic performance, analyzing the phenomena, and optimizing the design of the axial flow pump is very cost-effective and flexible. This study is performed to clarify the difference between steady and unsteady simulations based on the axial flow pump. Numerical simulations are carried out using the steady and unsteady Reynolds-averaged Navier-Stokes (RANS and URANS) equations and a shear stress transport reattachment modification turbulence model with small y+ values at all wall surfaces. To show the accuracy, numerical simulations are analyzed and compared with testing results. The difference in steady and unsteady simulations is presented by a detailed analysis of the flow field under the deep stall condition. The result shows that the numerical and testing results are in good agreement with each other. However, the unsteady results are more accurate than the steady results, especially in the saddle zone. Under deep stall condition, it is difficult to accurately predict the hydraulic performance and fluid flow characteristics inside the axial flow pump through steady simulation because of the time-dependent flow.