| Regulating valve-pipeline system plays a very important role in modern industrial process control,and its overall dynamic characteristics affect the performance of the whole industrial control process.The vibration and mutual coupling of the control valve and the pipe itself cause many safety accidents and affect the economic efficiency of the enterprise.In this paper,taking the regulating valve-pipe conveying fluid as the research object,reveal the vibration law of the system by the transfer matrix model and the finite element model of the system are established,analyze the inherent characteristics and dynamic response of the system,reveal the vibration law of the system.First of all,In order to study the dynamic response of the regulating valve itself,and in order to verify the analytical model and the finite element model to solve the consistency,the differential equation of motion.of spool-stem system of pneumatic diaphragm single-seat valve is established,and the inherent characteristics and dynamic response of the spool-stem system under different working conditions are numerically solved.The finite element model of valve body and spool-stem system is established,and the inherent characteristics,frequency domain and time domain analysis of the regulating valve are carried out,and the results of the two methods are consistent.The research shows:for a given opening,with the increase in pressure,the valve spool-stem system natural frequency increases,the larger the spool offset;for a given differential pressure,as the opening increases,the natural frequency of the spool-stem system decreases and the spool is less.Secondly,in order to study the dynamic response of the regulating valve-flow pipe coupling system and verification of the effectiveness of the transfer matrix to solve the complex fluid-solid coupling system.The differential equations of linear fluid-solid coupling motion of the pipeline are established,and the transfer matrix at both ends of the pipeline is deduced;According to the discrete model of the elbow,the transfer matrix of the elbow is established;According to the relationship between the dynamic model of the spool-stem and the state quantity at both ends of the valve body,the transfer matrix of the regulating valve is established;The transfer matrix of the flow straight pipe,the elbow and the regulating valve are multiplied in turn to establish the transfer matrix of the L-shaped and U-shaped pipeline and the transfer matrix of the regulating valve-flow piping system;Respectively,to solve the inherent characteristics of the pipeline and the regulating valve-the inherent characteristics of the pipeline system,frequency and time domain respons;The research shows:When the opening degree is given,the amplitude of the spool increases with the increase of the pressure difference,and the vibration amplitude of the valve with the valve is larger than that of the pipe.Finally,In order to verify the transfer matrix to solve the complex fluid-solid coupling system is correct,the finite element model of the pipeline and the finite element model of the regulating valve-flow pipeline system are established respectively,and the natural frequency and mode of the pipeline are analyzed empirically;The inherent characteristics,frequency domain and time domain analysis of the regulating valve-flow piping system under different pressure differential are analyzed when the opening degree of the regulating valve is given.Compared with the results of the transfer matrix method,the two methods are consistent.The research shows:the effect of pipe vibration on the vibration of the spool can not be neglected in the regulating valve-flow system analysis. |
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