Effect Of Swept Blade On The Performance Of Axial Flow Pump

Submersible axial flow pumps are widely used in pumping stations and municipal drainage fields.Because the working environment is underwater and the daily management and maintenance are inconvenient,the stable operation of submersible axial flow pump is very important.This paper focuses on the sweep design of the blade and its influence on the performance of the axial flow pump.The main work is as follows:1.On the basis of the original test-bed,the pipeline system suitable for this model was redesigned,and the required instruments were selected,and the test-bed was built.2.The external characteristic test of the pump has been completed and the reliability of the test-bed has been verified.The numerical results of the external characteristics of the submersible axial flow pump are obtained by numerical simulation,which are in agreement with the experimental results.3.The swept blades of 20,40 and 60 degrees are designed.The effects of swept blades with different swept angles on the external characteristics,cavitation performance and internal pressure fluctuation of the axial flow pump are investigated by numerical calculation.From the simulation results of the external characteristics of the axial flow pump,it is found that the blades with suitable sweep angle can improve the hydraulic performance of the pump and prolong the high efficiency area of the pump operation.The head and efficiency of the 20 degree swept vane pump are higher than those of the prototype pump,and the performance of the four schemes is better.From the results of numerical simulation of cavitation,it is found that the larger the sweep angle is,the more prone the pump is to cavitation.However,under the same inlet pressure,swept blade can improve the gas volume distribution on the blade surface.The larger the sweep angle is,the smaller the gas volume fraction is.Generally speaking,the inlet pressure of the 20 degree swept blade is only 3KPa higher than that of the prototype pump when cavitation occurs,and the overall performance is better.From the simulation results of pressure fluctuation,it is found that the 40 degree swept blade has the best effect on improving pressure fluctuation,so the appropriate angle swept blade can improve the stability of operation.With the decrease of pump inlet pressure,the amplitude of rotation frequency and low frequency region at each monitoring point increases,and the amplitude of low frequency region increases most obviously at the outlet of guide vane.The Cavitation Fault Diagnosis of axial flow pump can be carried out by monitoring the change of pressure fluctuation amplitude at the outlet of guide vane.When the amplitude increases 11.3 times,the cavitation of pump can be judged.