Dynamic Characteristics Analysis Of Three-Way Spring Regulating Valve-pipe System

Spring regulating valves are widely used in pipeline transportation systems due to their simple structure and rapid adjustment.However,due to their sensitive nature to excitation,they are prone to interact with surrounding fluid media,generating flow induced vibrations and causing instability in the pipeline system.This poses a huge challenge to the safety and reliability of equipment,and can seriously affect the normal operation of the system.Previous research has mostly focused on a single valve unit,and the research on the transient dynamic characteristics of valves coupled in pipeline systems has not been in-depth.Therefore,studying the mechanism and control methods of fluid and valve interaction in pipeline systems has important theoretical guidance significance.This article focuses on the phenomenon of continuous vibration of a new type of three-way spring regulating valve under low flow conditions,with the aim of revealing the mechanism and inducing conditions of system instability,and eliminating abnormal valve vibration.Theoretical analysis,numerical calculation,and simulation simulations have been conducted.The main tasks are as follows:(1)Introduce the modeling and solution methods of pipeline valve coupling system.Theoretical analysis was conducted on the fluid dynamics in the pipeline and the simple valve core model.Previous studies have shown that the dynamic characteristics of the valve core need to consider the influence of upstream and downstream boundaries.Therefore,based on the theoretical analysis,a calculation model for the simple pipeline valve coupling system was constructed,and the feasibility of the model coupling method and numerical solution method was verified by comparing with experimental data.(2)Research on the steady-state characteristics of a new type of three-way spring regulating valve.Due to the difficulty in accurately describing the flow coefficient and fluid excitation of complex valves using theoretical formulas,a CFD simulation model for three-way spring regulating valves is established.Firstly,the accuracy of the CFD simulation model was verified through experiments.Then,the flow characteristics of the valve and the law of fluid force acting on the valve core were studied under different valve openings and flow conditions.The calculation results indicate that the flow coefficient of the main outlet and bypass port of the three-way spring regulating valve is mainly related to the valve opening,and the fluid force acting on the valve core is mainly related to the flow distribution relationship at the valve outlet and the valve opening.Finally,the flow coefficient and fluid excitation expression were obtained through a combination of data fitting and theoretical analysis.(3)Research on the dynamic characteristics of the coupling system of three-way spring regulating valve and pipeline.Firstly,the flow coefficient and fluid excitation of the three-way spring regulating valve were coupled into the pipeline system,and a dynamic numerical model of the three-way spring regulating valve pipeline coupling system was established.Then,the coupling model of the three-way spring regulating valve pipeline was verified through CFD simulation calculation.Then,the evolution law of system instability and the type of valve core vibration under low flow conditions were explored,as well as the response of the system under fluctuating flow conditions.The calculation results indicate that when the flow rate of the system is less than the critical flow condition,the system will lose stability and generate self-excited oscillation,with the vibration frequency close to the characteristic frequency of the pipeline;Under fluctuating flow conditions,when the excitation frequency of the incoming flow is close to the characteristic frequency of the pipeline,it can cause severe vibration of the valve core,so this situation should be avoided.(4)Exploring the Factors Influencing the Dynamic Characteristics of a Three way Spring Regulating Valve Pipeline Coupling System.In response to the self-excited instability phenomenon of the system under low flow conditions and the dynamic characteristics under the excitation of incoming flow fluctuations,the influencing factors were explored from three aspects: valve parameters,bypass port action,and pipeline parameters.The role of different parameters in system response has been clarified,providing theoretical and technical support for the selection and configuration of valves in pipeline systems.