Numerical simulation of solid-liquid two-phase turbulent flow in swept-back sewage centrifugal pump

Abstract

Three-dimensional simulation was performed for the solid-liquid turbulent flow in swept-back sewage centrifugal pump with particle model and simplec algorithm by ANSYS-CFX software. k - ɛ double turbulence model was applied to predict the liquid-phase, and an algebraic named the dispersed phase zero equation was adopted to predict the solid-phase. Free slip wall conditions were used for mass and momentum. Solid particles on the distribution of the pump and the slip velocity were studied in order to further analyse the wear and tear of flow components as well as the influence law of pump hydraulic external characteristic was also researched. It is found that solid particles mainly accumulate near the cutwater of volute. Slip velocity of solid particle is significantly increased on pressure side and back side of suction side of rear shroud, indicating wear of the wall is exacerbated, therefore, the shroud should be thickened when designed. In addition, solid particle size and solid volume fraction have an influence on the pump hydraulic external characteristic in different degrees, of which the hydraulic head and pump efficiency drops with the increase of particle side, while the hydraulic head increases and pump efficiency declines with the increase of solid volume fraction.