Study on Internal Vorticity Dynamics of Centrifugal Pump Volute Based on DDES

In order to study the vortex structure and the process of vortex evolution in the volute of centrifugal pump, the unsteady numerical simulation of vortex motion of centrifugal pump under multiple working conditions was carried outbased on the DDES turbulence model and the vorticity of vortex dynamics.Compared with the numerical simulation and experimental data of the characteristic, the difference between the two values was in the allowable range.This means the Delay Detached Eddy Simulation is reliable. Compared with the vorticity cloud images, DDES turbulence model obtains more clearly image to see the small vortex formed by the collapse of the large vortex and simulate the fine flow field structure better than RNG k-ε epsilon turbulence model. The vortex in the volute was mainly concentrated in the vicinity of the inlet and the tongue. The vortex flowed with the fluid, the large vortex was broke down into many small vortices, and the vorticity decreased gradually. As the flow rate increased, the vortex distribution in the flow path and the vorticitydecreased gradually. In the third section of the volute, three pressure fluctuation monitoring points were taken along the radial direction, and the pressure fluctuation decreased gradually with the of diameter increasing, and the pressure fluctuation of the tongue was much larger than that of the other parts of the volute.