Transfer Matrix Modeling And Dynamic Simulation Analysis Of Complex Flow Pipeline-regulating Valve System

The pipeline-controlvalve system is an important part of the process industrial production,Its dynamic performance and reliability affect the stability and safety of the production.Most previous studies only considered the effect of fluid-solid coupling,but ignored the interaction between the regulating valve and the pipeline,which could not reveal the mechanism and laws of the vibration of the valve-fluid-pipe coupling system.In this paper,the complex flow pipeline-regulating valve is taken as the research object,the dynamic response of the complex flow pipeline-regulating valve system is analyzed.Firstly,a nonlinear dynamic model of the valve core-stem considering the pressure of the air chamber film,fluid unbalance force,frictional force and spring restoring force is established.Using the Runge Kuta numerical calculation method,the nonlinear vibration response of the spool under different operating parameters was analyzed,and the bifurcation diagram of the valve core vibration with the pressure difference at both ends of the regulating valve and the opening of the valve core is given,revealing the process of spool vibration bifurcation to chaos;At the same time,it shows that the condition of collision with the bottom of the valve seat at a small opening of the spool not only depends on the opening of the spool,but also the pressure difference between the two ends of the valve size related.Secondly,based on the fluid-solid coupling physical model of the 14 pipeline,for the straight pipe,curved pipe and branch pipe,and considering the coordinate transformation between different-sided pipes and the elastic support of multi-span pipes,a complete space with the transfer matrix modeling method of complex flow pipelines with different plane configurations,multi-span elastic/rigid supports,and serial-parallel mixing;Using the transfer matrix method and finite element software simulation,the inherent characteristics of different flow pipeline models are analyzed.The relative error of the results of the two methods is within 10%,indicating the correctness of the transfer matrix modeling of each model and the feasibility of modeling complex pipelines.The efficiency of the transfer matrix method is hundreds of times that of the finite element simulation.In addition,when the flow channel introduces constraints in the middle,the change of the spring support position,number and stiffness has a greater impact on the low-order frequency of the system,and the high-order frequency is less affected by it,when the stiffness of support increases to a certain value,it can be considered that the stiffness of support approximately meets the requirements of rigid support.Thirdly,the control valve is established in the same order as the state variable of the flow pipeline,and the transfer matrix model of the linearized control valve is established.According to the idea of the chain system transfer,the specified complex flow pipeline-control valve system transfer matrix is constructed.By making different assumptions and solving for the flow pipeline-regulating valve model,the results show that the vibration response of the integrated flow pipeline-regulating valve system is larger than that obtained by considering the flow pipeline or the regulating valve alone7%?50%.Therefore,it is necessary to integrate the model analysis of the regulating valve-transport pipeline.in the dynamic analysis and design of the system,both the regulating valve and the flow pipeline must consider the influence of the interaction.Finally,in order to solve the dynamic response analysis problem of the integrated system of linear pipeline and nonlinear regulating valve,the time domain response of the state variables at any time of pipeline is solved by the discrete time transfer matrix method of multi-body system transfer matrix method.By combining the multi-body discrete-time transfer matrix method with the nonlinear dynamic method,the transient solution of the pressure difference of the pipeline is taken as the bifurcation parameter of the valve stem under the action of the flow pipeline.The results show that the vibration mechanism of regulating valve core-stem becomes more complicated under the action of flow pipeline,and the vibration of valve core will vibrate up and down with the pressure difference near the stable value,which will lead to the rapid jump of valve core vibration during different periods.