Vibration Response And Modal Analysis Of Infusion Piping System During Valve Opening And Closing

The infusion piping system is usually provided with a valve structure,the fluid flow in the infusion pipeline is controlled by closing and opening valves.The fluid fluctuation caused by the valve in the process of opening and closing will produce the water hammer,resulting in the violent vibration and noise of the pipeline,and even the safety accident of the pipeline system.Therefore,the study of the vibration characteristics of the infusion piping system and the dynamic response of the pipeline during the valve opening and closing is of great value for the design,verification and evaluation of the vibration noise and structural safety of the infusion piping system.This paper studied the fluid-solid coupling transient and modal responses of a practical infusion piping system with a single butterfly valve and some elastic supports.Firstly,the bidirectional fluid-solid coupling technology in ANSYS Workbench platform is used to conduct transient analysis on the fluid-solid coupling interaction of the pipeline near the valve in the process of valve opening and closing,so as to obtain the flow field distribution and structural response of the pipeline during the process of valve opening and closing.Secondly,based on the classical Euler-Bernoulli beam theory and the differential equations of axial,circumferential and transverse fluid-solid coupled vibration of the pipe,the finite element formulation of the pipe element considering fluid-solid coupling vibration are established.And the fluid-solid coupling pipe element was added to ANSYS using the UPFs secondary development function.Then,numerical example is used to verify the accuracy and efficiency of the custom fluid-solid coupling pipe element.On this basis,the custom fluid-solid coupling pipe element is used for modal analysis of a practical infusion piping system,and the natural frequency of the pipe system is obtained.It is found that the maximum amplitude of the corresponding mode shapes is at the position of the valve component,and the influence of the stiffness,number and position of the elastic support on the natural frequency and formation of the pipeline system is obtained.Finally,the bidirectional fluid-solid coupling analysis was carried out on a practical infusion piping system with a single butterfly valve and some elastic supports,and the influence rule of the valve closing time on the water hammer and the vibration characteristics of the piping system was studied.The results show that the peak pressure of water hammer and the peak vibration displacement of pipeline increase with the increase of the closing speed of the valve,while the pressure of water hammer decreases with the increase of the distance from the valve.Then,the empirical formulas describing the distance between water hammer pressure and valve,the peak of water hammer pressure and valve closing time,the peak of pipeline vibration displacement and valve closing time are obtained by curve fitting.