Numerical Simulation And Structure Optimization Of Self-priming Pump

As a special kind of centrifugal pump,self-priming pump had been mainly used in special industrial area.The self-priming pump needs to be pumped before it first starting,and no need to pumped start again later.Based on the results of domestic and foreign scholars about the self-priming pump,the self-priming process was further discussed in this paper.First of all,the structure and principle of vane self-priming vertical pump were introduced,and the impeller and guide vane,the key part of the pump,were designed;the liquid phase steady working condition of self-priming were simulated be CFX software,the absolute velocity,relative velocity and pressure distribution in the impeller flow passage were analyzed.Then the estimated performance curves of the pump and the test performance curves were compared,and both are well matched,thus,the model proved good.Then,a unsteady numerical simulation was applied to simulated the self-priming process of self-priming pump,with the initial condition was that the inlet and outlet pipe filled with air.The gas-liquid two phase distribution and flow evolution in impeller and guide vane in the pump during self-priming process were analyzed.The flow rate of gas phase with time at the impeller inlet and outlet of the pump were obtained by functions that provided by CFX,and then self-priming time was estimated by flow rate of gas phase in the pump outlet;Due to the gas-liquid separation chamber is the main place for gas-liquid mixing and separation,therefore,the influence of baffle in the separation chamber on self-priming process was analyzed,and also compared the results with that no baffle in the separation.Finally,the orthogonal simulation design has been worked on the self-priming pump.Based on analysis,four factors which had an effect on performance of self-priming were selected for orthogonal simulation design;by processing and analysis of data,influence degree of different factors was obtained,and the optimal scheme was obtained too.The clearance between impeller and guide vane is the main influencing factor of self-priming time and self-priming height were found by the index-factor graph;therefore,the influence of the clearance between impeller and guide vane on the self-priming time was further discussed.It was found that there was an optimum value for the gap.