Numerical Simulation Research On Flow Characteristics And Flow Induced Vibration Of Pilot Control Valve

The research was completed under the support of the National Natural Science Foundation of China(No.51569012).With the implementation of major national projects such as the third generation of advanced pressurized water reactor nuclear power,10 million tons/year refinery,and 1000 MW ultra-supercritical thermal power,the control valve has been proposed as a high-performance component as an important control component in the process.Compared with the traditional control valve,the pilot control valve has the advantages of good sealing performance,stable opening and closing,compact structure,etc.It is especially suitable for high temperature and high pressure large diameter occasions,and widely used in the modern automatic control industry.However,in the actual production and application,the pilot control valve in the normal operation and opening and closing process appeared the problem of vibration of the valve core components and the pressure and flow imbalance after the valve,seriously affecting the normal operation of the whole valve control system.Based on the above problems,this paper carries out the following research work based on the computational fluid dynamics method:(1)The structure of pilot control valve was designed based on the principle of multi-stage pressure reduction and the compressible medium flow equation,The effect on the turbulent wall friction coefficient and profile velocity distribution of reynolds number and watershed discrete method were researched based on the classical turbulent model of curved pipe,and the numerical simulation method for accurately calculating the flow field in the turbulent flow of the pilot control valve was obtained,which laid the foundation for the turbulent flow field calculation and flow-induced vibration of the pilot control valve.(2)The numerical simulation model of the valve core assembly with different structural parameters was established based on the orthogonal optimization test method,and the steady flow field of the control valve was simulated by ANSYS CFX software.CEL language was used to monitor the force on the surface of the valve core,The influence of the control valve structural parameters on the force acting on the valve core assembly is studied,and last,the structure optimization of valve core assembly was studied.(3)The transient flow field of the pilot control valve was calculated to obtain the pressure pulsation characteristics at different points based on the CFD method.The influence of the valve opening on the pressure fluctuation at different points in the ba sin is studied by the pressure fluctuation frequency domain analysis method.The pressure fluctuation amplitude of the pilot control valve in a certain frequency range was obtained,which provided a basis for the vibration analysis of the valve core assembly.(4)The vibration mechanics model of the control valve spool was established based on the thermal fluid-solid coupling modal analysis method and the structural resonance analysis method,the effects of prestressing force,spring force and an adjusting valve opening on the modal frequency of the valve core assembly were studied.The optimal working condition of the control valve was obtained,which provided a basis for the anti-resonance design of the control valve.The above research provides a reference for the structural design of the pilot type control valve,It had guiding significance for the vibration suppression design of the valve core assembly of the pilot control valve by analyzing the influence of the transient flow field and structure on the modal of the pilot control valve.