Research on Cavitation and Mechanism of Multistage Pumps Based on Auxiliary Blades

To reveal the cavitation suppression mechanism of front shroud auxiliary blades in five-stage centrifugal pumps under low-flow conditions, comparative numerical simulation and experimental test were carried out. The full-flow CFD model combined with standard k-ε turbulence and homogeneous equilibrium cavitation models was established, and external characteristic experiments verified simulation precision. Cavitation performance, pressure distribution, vapor volume fraction and wear-ring leakage were analyzed at 0.3Q low flow rate under varying inlet total pressures. Results show that auxiliary blades reduce critical cavitation margin by 0.69 m at design flow rate, raise cavitation head by 2.89 m and shrink cavitation coverage significantly. Auxiliary blades suppress wear-ring leakage, elevate internal impeller pressure and cut turbulent kinetic energy dissipation. The cavitation expansion rate of auxiliary blades structure is much lower as inlet pressure declines. This study clarifies the cavitation regulation mechanism of auxiliary blades, providing theoretical reference for anti-cavitation structural optimization of multistage centrifugal pumps.