Influence Of Wear-ring Clearance Incident Angle On Internal Flow And Vibration In Centrifugal Pump

Centrifugal pump is a kind of general equipment which is widely used in industry,consume 20% proportion of Power generation.So,It has great practical value to study and improve the efficiency and stability of centrifugal pump.The high-energy fluid leaking from the centrifugal pump wear ring will disturb the inlet fluid,which makes the inlet flow complex and causes energy loss,effecting the efficiency and stability of the centrifugal pump.In this paper,researching a low specific speed closed impeller centrifugal pump.The incidence angle of the wear ring clearance is changed,by changing the pump body and the front cover plate of the impeller,in order to reduce the disturbance of the high-energy fluid leaking from the wear ring clearance to the inlet.s The SST k–ω numerical simulation method is used to analyze the effects of different incidence angles of the wear ring clearance on performance,flow characteristics,cavitation distribution and pressure pulsation of the centrifugal pump,and the vibration characteristics Under the design condition.The main research contents and conclusions are as follows:(1)The flow field domain and impeller rotor domain of centrifugal pump with different incidence angles were modeled.The numerical simulation was carried out by ANSYS fluent and ANSYS Workbench software.The simulation results were compared with the experimental results of the performance of the prototype pump(IA90),the pressure pulsation of the monitor points and the vibration of the monitor points,which verified the accuracy of the numerical simulation results.(2)Through numerical simulation,the relationship between the performance and leakage of centrifugal pump between the different incidence angle is analyzed.It is found that the leakage decreases with the decrease of the incidence angle of the wear ring clearance,thus the efficiency and head increase.By analyzing the circumferential velocity near the wall of the inlet section to analyze the occurrence of reflux pre rotation,it is found that the decreasing of the incidence angle can reduce the internal circulation of the inlet section of centrifugal pump,It is found that the change of the incidence angle of the ring gap has a greater effect on the entropy of front cavity basin and the impeller basin,while the change of the incidence angle has little effect on the back cavity basin and the volute basin.With the decrease of the incidence angle of the ring gap,the total entropy production of the centrifugal pump decreases gradually.The influence of the incidence angle on the cavitation performance is analyzed,It is found that the cavitation in centrifugal pump can be restrained by decreasing the incidence angle.(3)Through the analysis of the frequency domain diagram and pressure fluctuation energy of the centrifugal pump monitor points with different incident angles,it is found that the main frequency amplitude and pressure fluctuation energy of the pressure fluctuation in the wear ring clearance decrease with the decrease of the incident angle,but change little with the increase of the flow rate;the main frequency amplitude and pressure fluctuation energy at the inlet of the impeller also increase with the increase of the incident angle,However,it is greatly affected by the change of flow rate.(4)It is found that the radial force,vibration displacement amplitude,vibration energy and equivalent stress of the impeller rotor increase with the decrease of the incidence angle.