Study On The Flow Characteristics Of The Flow Field In The Fluoroplastic Magnetic Pump

The fluoroplastic magnetic pump uses a motor to drive the external magnetic rotor,and the magnetic force among the internal runner and the external runner makes the internal runner turn round synchronously with the external runner.The internal magnetic rotor is completely enclosed by an isolation sleeve to form a static seal structure,which eliminates the possibility of medium leakage in the structure.The lining of fluorine plastic material eliminates the phenomenon of magnetic eddy current,but also greatly improves the corrosion resistance of the pump.This makes fluoroplastic magnetic pumps widely used in the petroleum industry,non-ferrous metals,electroplating,pharmacy and other areas.The development of the country has made environmental problems more and more serious.The non-leakage and corrosionresistant fluoroplastic magnetic pump accords with the national environmental governance.Thus,enhancing the theory and performance research of fluoroplastic magnetic pump is of farreaching significance.In this paper,the flow characteristics of flow field in fluoroplastic magnetic pump CQC100-65-220 are studied by numerical simulation.The specific research contents are as below:(1)The differences of numerical simulation methods on the market are balanced,and lastly the two-equation model in the vortex viscosity model is selected for calculation.The advantages and disadvantages of the two-equation turbulence model offered in ANSYS FLUENT are analyzed by synthesis.The SST k-ω model is the model which mixed the k-ε model and the k-ω model up.It is more suitable for the flow of small gaps in the fluoroplastic magnetic pump.Therefore,the SST k-ω turbulence model was finally selected.(2)A constant value simulation analysis was carried out on the full flow field of the fluoroplastic magnetic pump.This paper uses numerical simulation method,the flow characteristics of the flow domain in the fundamental flow units of the fluorine plastic magnetic pump under different flow conditions are obtained.The pressure distribution in the pump is uniform The main reason for the flow field disorder in the impeller passage is the collision between the return medium of the balance hole and the inlet medium of the impeller.The wear mechanism of the abnormal wear of the dry friction bearing of the fluoroplastic magnetic pump in realistic function is analyzed,and the endings make clear that the big pressure differential on both flanks of the unlubrication friction bearing is the main account for the abrasive wear.(3)The whole flow field of fluoroplastic magnetic pump was simulated and analyzed.Based on the results of steady state analysis,a time term is introduced to obtain the value of pressure pulsations of the main flow portion at different flow conditions by means of a method that sets the monitoring point of the main flow portion of the fluoroplastic magnetic pump.The distribution law was analyzed comprehensively.It is found that the frequency of pressure fluctuation is mainly affected by the passing frequency of impeller.Local pressure variation caused by dynamic and static interference between impeller,volute and tongue were found to be the main source of pressure pulsation in the fluoroplastic magnetic pump,and the pressure pulsation propagates through the medium to the cooling circulation channel of the high pressure area of the pressurized water chamber.Entering the cooling circulation channel,the pressure pulsation intensity will gradually attenuate during the propagation process.(4)Experimental verification of external characteristics of plastic magnetic pump.Through the experimental device,the actual operation data of fluoroplastic magnetic pump under different flow conditions were tested and calculated,and the differences between simulation and experiment were compared and analyzed,the results show that the simulation results are reliable.The neglected volumetric efficiency,mechanical efficiency and surface roughness of overcurrent components are the main reasons for errors between the simulation results and the experimental results.