Study on the flow pattern and pressure fluctuation in a vertical volute centrifugal pump with vaned diffuser under near stall conditions

The vertical volute centrifugal pump is widely used in the long-distance water division project. Flow separation and vortex phenomenon can be observed vaned diffuser under near stall operating conditions. This kind of unsteady flow structures would result instability unit which affect safety reliability operation. In this paper, patterns induced pressure fluctuation a with were simulated based on SAS turbulence model refined mesh research results show that SST combined selected grid validated CFD uncertainty analysis during steady calculation ITTC relevant procedures. performance predicted by quite good agreement experimental data, prediction errors less than 5%. 3D matching between angle at impeller blade outlet incidence guide vane different spans induce inception pump. conditions revealed vorticity streamline distributions. When was operated conditions, main frequency changed from passing 7fn to 0.9fn. It found mainly affected large-scale vortices diffuser, appear every 0.9 time period one revolution impeller.