Analysis Of Hydraulic Flow Induced Vibration Response Of An Engineering Vane Centrifugal Pump

Centrifugal pump is a kind of rotating machinery conveying fluid,during operation,the relative motion between rotating parts and static parts will produce strong dynamic and static interference,the dynamic and static interference will lead to the pressure pulsation in the flow field of centrifugal pump,and the pressure pulsation is one of the main reasons to induce the structural vibration of centrifugal pump,it is an important reason for structural vibration of centrifugal pump and equipment damage and failure.It is of great significance to study the vibration of centrifugal pump structure induced by pressure pulsation in the flow field of centrifugal pump.In this paper,an engineering vane centrifugal pump is taken as the research object to analyze the flow induced vibration characteristics of the centrifugal pump system structure under the fluid excitation of the inlet pipe,volute,impeller and outlet pipe.Firstly,the fluid structure coupling method of the centrifugal pump system structure is explored,and the way of mapping the flow field load to the structure is designed;Then,based on a flow field calculation software,the flow field of centrifugal pump is calculated,the pressure fluctuation and excitation characteristics of flow field are analyzed,and the fluid load of rectification field is extracted;Finally,based on a structure calculation software,the flow induced vibration response of centrifugal pump system structure under rectifier field load and local load is calculated,the vertical vibration response results of the base are extracted,and its characteristics are analyzed.The main results are as follows:（1）The blade frequency（blade frequency）of the impeller is 290Hz,which is the main pressure fluctuation in the volute basin and outlet pipe basin,the closer the monitoring point in the volute basin is to the volute tongue,the more obvious the pressure fluctuation is,this is due to the dynamic and static interference between the impeller and the volute tongue;The pressure pulsation is not obvious at the monitoring points in the inlet pipe basin,but obvious at the monitoring points close to the impeller basin,which is because it is not affected by the impeller disturbance;The main frequencies of the resultant forces and torques on the impeller are the rotor rotation frequency（shaft frequency）48.33 Hz,5 times shaft frequency241.6 Hz,blade frequency 290 Hz and double blade frequency 579.9 Hz.（2）The vertical vibration displacement amplitude of the base is small,and the order of magnitude is 1×10^-6m,the acceleration amplitude is also small,with the order of 1m/s²;The vibration displacement and acceleration frequency of the base are mainly reflected in the frequency of the flow field load,and there is also the natural frequency of the structure;Because the excitation of 5 times of axial frequency on impeller is close to the 8th natural frequency of centrifugal pump system structure,the displacement amplitude and acceleration amplitude of these two frequencies are higher;The amplitude and frequency of the displacement and acceleration of different nodes of the base are different,which is also caused by the asymmetry of the centrifugal pump structure,the position of the load and the position of the constraint;The main flow field loads that induce centrifugal pump vibration come from volute and impeller.