Numerical Simulation And Experimental Study On Liquid-Solid Two-Phase Flow In Vortex Pump

Research works in this paper are financed by the item of National Science Fund of China "study on the liquid-solid two-phase flow with salt-out in turbine machines". (No.50476068)Vortex pump is widely used on sewage sludge treatment and hydraulic transport of solid. At present, understanding of the real internal flow rule in the pump is not enough. In order to prove up the law of liquid-solid two-phase flow in vortex pump and make foundations for study on the theory of liquid-solid two-phase flow with salt-out in turbine machines, the liquid-solid two-phase flow field in a vortex pump was studied in this paper based on the former researches. A vortex pump was designed. Numerical simulation and experimental researches were used. The main works and conclusions are showed as following.1. Present research states of vortex pump and liquid-solid two-phase flow were introduced simply. Methods of hydraulic and structural design of the pump were expounded. A model pump, which met the measurement needs, was designed and manufactured based on the methods.2. Pro/E was applied to sculpt the model pump. The unstructured grids were generated in the area of flow passage in the pump. In order to improve the grid quality and quicken the solution velocity, local encryption techniques were adopted.3. Euler multiphase flow model and modified k -εturbulent model were adopted to simulate internal liquid-solid two-phase flow field at the best efficiency behavior of pump. Axial cross-sections and regions were plotted to locate every measure point and display the results for comparing with the measurement results. Conclusions were obtained such as that "area of the lowest concentration of granule is at back side of blades near the back cover board and inlet of impeller".4. Measuring means on two-phase flow and internal flow of rotating machines with Phase Doppler Particle Analyzer (PDPA) were introduced.5. Experimental set were designed. The internal liquid-solid two-phase flow field in model pump was measured at the best efficiency by PDPA made by Dantec in Danmark.6. Experimental and calculation results were compared. Circumferential, axial and radial velocities and relative fluctuate velocities were analyzed. Conclusions were proposed such as "difference of circumferential velocities distribution of liquid-solid two-phase in impeller and volute of the pump".