Analysis of Thermal-Fluid-Structure Coupling and Resonance Forecast for Link Butterfly Valve Under Small Opening

When the link butterfly valve operates at a small opening degree in high temperature working conditions,it is prone to the problem that the valve is stuck,the strength is insufficient and the butterfly plate is violently vibrating.This paper shows simulation experiments of both thermal-fluid-structure coupling and resonance forecast about DN600 link butterfly valve in the working conditions of 250℃and 0.5 MPa by ANSYS software.The medium is mixed with compressed air and flue gas.Flow field characteristics of the valve and stress deformation,modal and flow-induced vibration of butterfly plate are analyzed when the valve opening is less than 30%.The results indicate that,when the valve opening is less than 30%,fluid flow is relatively smooth in front of butterfly plate,a large number of vortexes are found behind the butterfly plate,and fluid flow is greatly chaotic in this position.The equivalent maximum stress and deformation of butterfly plate are relatively large when the valve locates in openings between 10%and 30%;the intensity of the butterfly plate is enough;the axial deformation does not impact opening and closing of the valve.The butterfly plate is likely resonant when the valve opening is less than 10%.The research of this paper provides a crucial reference for flow field characteristics of link butterfly valve,an analysis of intensity and rigidity of butterfly plate,and a resonance forecast of butterfly plate when the valve works in small opening.

Dynamic rupture of metal sheet subjected to laser irradiation and tangential subsonic airflow

To reproduce the premature rupture process of metal sheet subjected to laser irradiation with subsonic airflow,which is an interesting phenomenon observed in the experiments given by Lawrence Livermore National Laboratory,a coupled numerical model considering the interaction and evolution of metal elastoplastic deformation and aerodynamic pressure profile is presented.With the thermal elastoplastic constitutive relationship and failure criterion,the simulated failure modes and dynamic rupture process are basically consistent with the experimental results,indicating plastic flow and multiple fracturing is the main failure mechanism.Compared with the case of non-airflow,subsonic airflow not only accelerates deformation,but also turns the bugle deformation,plastic strain and rupture mode into asymmetric.