Numerical investigation on cavitating flow and cavitation-sand erosion characteristics of a centrifugal pump under sand-laden water conditions

Purpose The objective of this investigation is to analyze the cavitating flow of sand–laden water in a centrifugal pump and its induced cavitation–sand erosion mechanism. Design/methodology/approach An improved partially-averaged Navier–Stokes turbulence model and a zero-equation model are applied to discuss the mechanism of sand impact on cavitating flow. Meanwhile, the effect of sand on cavitation–sand erosion is analyzed by using a mathematical model. The cavitation performance curve and cavitation evolution of the centrifugal pump predicted by numerical simulations are in good agreement with the experiments. Findings The sand promotes the inception and development of cavitating flow in the pump. Meanwhile, the inception and development of cavitating flow force sand to distribute near the pressure surface of blade, especially in the upstream area of flow channel. It is worth noting that the increase of sand concentration enhances cavitation–sand erosion, and the increase of sand diameter prevents this process. Cavitation erosion plays a dominant role in cavitation–sand erosion. Originality/value The interaction law between sand and cavitation in the cavitation flow field of centrifugal pump under the condition of sand–laden water was studied, the dominant role of cavitation erosion and sand erosion in cavitation–sand erosion was obtained, and the influence laws of NPSH, sand concentration and sand diameter on cavitation–sand erosion characteristics of centrifugal pump were discussed. The results can provide reference for the optimizing design and increasing service life of pump.