Study On Flow Excitation And Vibration Characteristics In A Vertical Centrifugal Pump

The centrifugal pump as a machinery has been widely used in many industries.The pump has not only met the demand of hydraulic performance,but also the vibration requirement.Once vibration levels are high,it can cause unstable working and equipment trouble and so on.The research idea of the paper is force-pathways-response.Based on the steady analysis of the flow field,the characteristics of unsteady flow and flow excitation are studied by fluid-structure interaction.The establishment of the finite element model and transient dynamic analysis are used to study the flow excitation and vibration characteristics.The vertical centrifugal pump is taken as the research object.The main content is as follows:(1)The flow field is meshed into elements.The numerical simulation and test results of the hydraulic performance are compared.The pressure and velocity distribution of the volute in the circumferential and radial direction are calculated by numerical simulation.(2)Based on steady flow analysis,Interaction between structure deformation and flow excitation's impact on unsteady flow are analyzed by fluid-structure interaction.The influence of pressure on the impeller,volute,clearance and flow excitation is studied in time domain and frequency domain.The results of analysis indicate that the fluctuation variation considering FSI is more intense than that by transient flow analysis in time domain,especially monitors nearby the impeller.The results considering FSI in the frequency domain are different from it by transient flow analysis.(3)According to pressure characteristics of pump cavity and the clearance,boundary conditions and structures' influence on excitation induced by the impeller is explored.The mechanism of action about flow excitation induced by the impeller is studied by adjusting mass flow rate,clearance,balance hole diameter and cavity structure.The analysis of flow excitation induced by the impeller is to provide foundation for reducing vibration source.(4)The finite element model is established to analyze modal.The natural frequency is in good agreement with the experiment data.The flow excitation of impeller and volute is loaded by nodes loading.The vibration response of pump in mass flow rate is calculated by transient dynamic analysis.The vibration rules are verified with experiment data.