Simulation and Experiment on Flow Characteristics of Large Particles in Vortex Pump Based on DEM-CFD

In recent years, because the anti-clogging ability of swirl pump is better than that of ordinary pumps, it is gradually applied to more fields. However, when transporting sewage contains solids, it will still encounter problems such as half clogging, overwork wear, etc., so it is particularly important to master the flow characteristics of solid particles in the vortex pump. DEM-CFD coupling method was introduced into the numerical simulation of vortex pump. The movement law of particles in the pump was compared and analyzed when the vortex pump transported solid phase with different particle sizes and concentrations. The results showed that according to the experiment of rapeseed transportation by vortex pump, the calculated results of external characteristics were basically consistent with the experimental results. It was found that under the characteristics of the pump model, the particle rotation and flow caused by the circulation flow were more serious in the inlet pipe and the bladed area. The spiral flow from the chamber was reversed along the inlet wall, and the inlet flow was mixed with the reverse spiral flow to reach a balance. The experimental results were consistent with the numerical simulation results. It can be seen from the experiment that the calculation results of the pump performance were basically consistent with the experimental results, and it was found that the particle circulation and rotation phenomenon caused by the circulation flow existed in the inlet pipe, which was also one of the characteristics of the vortex pump and was consistent with the simulation phenomenon, which proved that the DEM-CFD coupling method had a certain reliability. It was found that there were three different modes of particle transportation in the swirl pump, the first was that particles flowed through the impeller and entered the volute, the second was that particles were directly thrown into the volute through the bladed cavity under the influence of circulation flow, and the third was that particles entered the impeller from the front end face area of the impeller and then entered the volute through the impeller. Through the analysis of internal flow characteristics of volute, it was found that the particles were mainly distributed at the back of the volute. From the diffusion section to the outlet area of the volute, the particles flowed out in a spiral way with the liquid, and the spiral vortices of different sizes were formed at the impeller side of the volute section. © 2020, Chinese Society of Agricultural Machinery. All right reserved.