Numerical Investigation of Pressure Fluctuation Induced by Rotor-Stator Interaction in a Mixed-Flow Pump

Abstract

To investigate the pressure fluctuation induced by rotor-stator interaction, the three dimensional unsteady turbulent flow in a high-specific-speed mixed-flow pump was simulated based on Navier-Stoke solver embedded with SST k-ω turbulence model and SIMPLEC arithmetic. Pressure fluctuations at four places including impeller inlet, impeller outlet, middle and outlet of guide vane were recorded during the unsteady numerical simulation, and the time domain and frequency domain of pressure fluctuation were analysed as well. Numerical results show that the maximum pressure fluctuation appears at the impeller inlet where the fluctuation amplitude is 2.48 times that at the impeller outlet and 16.6 times that at the middle of guide vane. The fluctuation at the impeller inlet becomes stronger with the deviation of flow rate from the design condition and the amplitude at 70% of design flow is 1.5 times that at the design flow rate. Rotor-stator interaction induced by the impeller blades has the greatest affect on the pressure fluctuation while the number of guide vanes has little effect. The results could provide the theoretical basis for the stable operation of mixedflow pumps to avoid hydraulic excitation.