Identification and analysis of the inlet vortex of an axial-flow pump

Axial-flow pumps are widely employed in urban flood control and drainage pumping stations. The inlet vortex is one factor that seriously threaten the safe, stable and efficient operation of axial-flow pump units. In this paper, the vortex recognition performances of two vortex identification methods, the Q - criterion and Liutex methods, are compared based on an axial-flow pump, and the interactions between the impeller and vortex are explored. A flat plate vortex generator is installed in front of the impeller to continuously induce a stable vortex. The numerical simulation results show that the Liutex method can not only simultaneously identify strong and weak vortices but also reduce the influence of shear force at the sidewall. The vortex and the impeller influence each other. Under the influence of rotating blades, the vortex changes from a low frequency to the blade frequency, and the vortex significantly changes the tangential velocity inside the impeller. The accuracy of the numerical simulation results is verified by experiments on the external and internal characteristics.