Study On The Hydraulic Performance And Self-priming Characteristic Of A Double-stage Self-priming Pump

Self-priming centrifugal pump has a good self-priming performance and it doesn't need priming before starting again,so it is easy to automate control and widely used in important industrial and agricultural areas.The demands of the energy consumption of pumps in all kinds of applications are increasing.For examples,some problems exist in vertical self-priming pump widely used in the market,such as low hydraulic efficiency,poor running stability and self-priming performance and so on,the pump has been increasingly difficult to meet the needs of the application.In this paper,based on a vertical self-priming pump,a new design of two-stage vertical self-priming pump was developed.In this pump,based on the local euler head distribution,the inner energy distribution of the impeller was changed,the hydraulic performance of pump was improved,the structure of the new volute gas-liquid separation chamber was put forward,the sealing structure and the auxiliary impeller structure were improved.CFD code was used to improve the hydraulic model of the self-priming pump and estimate the performance,and the product was developed and field tested.Also,the two-stage self-priming designed in this paper has no backflow hole,the.self-priming characteristics of the pump was studied based on two phase flow simulation.In order to optimize the performance of vertical double-stage self-priming pump and study its self-priming characteristics,this paper mainly focuses on the following aspects:(1)The existing research results of typical self-priming pumps and the research status at home and abroad were summarized and the main studied problems of the vertical self-priming pump were studied and analyzed.A new structure vertical double-stage self-priming pump was designed and the hydraulic performance and self-priming characteristics were studied(2)Adopting ?—? turbulence model with the CFD code FLUENT,The single-phase flow steady CFD simulation of the inner flow field inside the pump and performance prediction was analyzed.According to the steady numerical simulation results,the volute and the internal structure of the impeller improved.The influence of the different structure on the flow field of the self-priming pump is compared and analyzed.The impeller,volute and pump internal structure of a high-efficiency self-suction pump were designed.(3)The design structure of two-stage vertical self-priming pump was tested.By comparing the test results of the pump performance with the simulation results,the rationality of the design and the reliability of the calculation method were verified.(4)The gas-liquid two-phase flow of two-stage self-priming pump was analyzed with the method of unsteady CFD analysis using the CFD code FLUENT.The gas rate,velocity,pressure distribution and flow characteristics in the pump were provided in the self-priming process.The pressure and gas rate in the inlet and outlet of impeller,the inlet and outlet of volute and gas-liquid separation chamber were analyzed to study the process of self-priming combined with the theoretical analysis.In this paper,the design of the new two-stage vertical self-priming pump was proposed.Flow passage components of the self-priming pump was designed and improved and the gas-liquid two-phase flow structures were studied in the self-priming process.Product prototype was manufactured and tested and applied to field application.The test and field application results indicated that the efficiency of the developed pump improved markedly compared with traditional pump and the self-priming characteristics were good which has met the purpose of energy-saving and cost-reducing.The researches of this paper provide for some reference value to the development and application of the vertical self-priming pump.