Transfer Matrix And Nonlinear Dynamic Analysis Of The Control Valve-conveying Pipeline System

The whole system of the control valve is very important in the process of industrial control,and its overall dynamic characteristics affect the performance of the whole industrial control process.But today many scholars study of this system are to stay in the pipes is separated from the body of research,not the combination of the whole reflect the overall dynamic response,therefore,in order to study the regulator-flow pipeline system as a whole the nonlinear characteristics and the influence of the pipeline vibration characteristics for regulating valve valve core,this paper established the regulator-flow pipeline system model,using the transfer matrix method of multibody system combined with dynamics method for solving nonlinear behavior and system response.The work is as follows.(1)Using Galerkin method and Newmark-β method,the nonlinear coupling phenomenon of the two supported planar transport pipeline is solved,and the research shows that the increase of axial force of the pipeline characteristic parameter increases the natural frequency.The increase of velocity will cause it to decrease;The first-order natural frequency value of the flow pipeline decreases with the increase of the parameter mass ratio,and the second order natural frequency increases with the increase of the parameter mass ratio.The increase of viscoelastic coefficient results in a slow rise in the first order natural frequency and a rapid decrease of the second order natural frequency.Relative to the stability of the pipeline,when the axial force increases,the static buckling critical flow velocity with increasing trend,and in dynamic instability,with the decrease of the axial pressure showed a trend of decrease,critical velocity and the increased linearly with the increase of axial tension.In addition,the critical velocity decreases with the increase of mass ratio and viscoelastic coefficient.Analyzed the nonlinear dynamic behavior of pipeline model,bifurcation diagram is drawn in excitation amplitude for control parameters respectively and time domain response and phase diagram,system is developed from quasi-periodic gradually way to chaos,and with the amplitude increases gradually,show the chaos movement and quasi periodic motion appear alternately,eventually maintain chaotic form.(2)By supporting space flow pipeline is studied,and the Newton’s method to launch with period pulsating flow and basic joint incentive under the simple harmonic motion mathematical model,and using the axial inextensible to simplify the partial differential equation of the three variables for the processing of two variables,using the Galerkin method and the discrete time transfer matrix method of multibody,transfer matrix model of the system are obtained.In this paper,the nonlinear dynamic analysis is carried out with the velocity as the parameter,and the system is simplified to be linear,and the transfer matrix model of axial,lateral and torsion is obtained by using the separation variable method.The results show that the nonlinear system is characterized by Paroxysmal chaos and chaos.Compared with the accuracy of the method used for the system of linear processing,the comparison of the method with the storage tank flow pipeline valve system(RPV)is not more than 7%.(3)In order to study the control valve-coupling dynamic characteristics of the flow pipeline system,established the control valve linear and nonlinear dynamics equation and the transfer matrix model,then the influence of pipeline on vibration of valve core is obtained.Research shows that:in the case of combined with linear flow pipeline,in the opening case,for the linear flow pipeline,valve core displacement vibration amplitude in a small range of values and small open degrees as the change of pressure difference showed a trend of increase,in the case of a wide range of values,each opening the valve core displacement amplitude decreases with the increase of the pressure difference;Under the condition of constant pressure difference,the increase of each pressure difference with the opening degree is increasing in the small range.A wide range of values,the differential pressure increases with the increase of the opening,first after decreasing trend,the greater the pressure value,the greater the amplitude of valve core,namely the selection of pressure shoulds not be too big,will lead to violent oscillation of valves in the valve core.For linear and nonlinear pipeline for valve core comparison shows that the influence of nonlinear pipeline for valve core displacement vibration amplitude is greater than the linear pipe,therefore,for the actual working condition and body safety,selecting model is more appropriate,nonlinear pipeline safety performance and higher control precision.