Study of the effect of solid particle volume fraction on cavitation characteristics in a centrifugal pump

摘要

The effect of solid particles volume fraction on cavitation characteristics during solid-liquid two-phase transportation was investigated in a centrifugal pump. The turbulent diffusion force, interphase drag force, and other forces between solid-liquid-gas three-phase are considered in this paper. The numerical simulation of cavitation flow in the solid-liquid flow field in the centrifugal pump is performed under designed flow condition, with the numerical simulation results being verified by experiments. The results show that when the volume fraction of solid particles is the same, the influence of the volume change of the bubbles in volute on critical net positive suction head is greater than that caused by the change of the volume of the bubbles in impeller. The average volume of bubbles in volute corresponds to the critical net positive suction head change trend. The size of separation vortexes generated by the sand-laden fluid on the suction surface of the blade is less with varying volume fractions of solid particles, whereas the size of the separation vortexes formed by tongue and VIII section of volute is bigger. The shaft frequency or the blade passing frequency is the main frequency of pressure pulsation at different positions in the pump. However, the structural instability of the flow field in the pump is attenuated by the volume fraction of solid particles, resulting in complex changes in the amplitude of the main frequency at different positions in the pump.