Wafer Ball Valve Theoretical Basis

The numerical simulation study of stress uniformity in valve Wafer Ball Valve aims to improve stress uniformity on the sealing surface within the specified sealing conditions, providing a theoretical basis for further optimized design of valve Wafer Ball Valve.
From the perspective of seismic analysis, the valve bonnet can be considered a "central support structure." Seismic activity in the pipeline system must pass through the bonnet before reaching the actuator assembly. Therefore, the bonnet must be able to withstand the dynamic effects of the actuator assembly. While the bonnet is a particularly strong component of the valve, its basic structure makes it difficult to analyze accurately.
Most control valve bonnets are analyzed using Appendix X1 of ASME I-III. Although this appendix is ​​typically used for analyzing pipeline flanges, it is generally recognized as suitable for analyzing bonnet flanges. Any seismic-induced bending forces on the actuator assembly are converted into a "high-value pressure," referred to as eq. 1. Thus, the design pressure of the valve increases. The bolts of the valve cover and the body cover must be able to withstand this increased flange structure pressure, pfd=pd+peq. ). During the sealing process, the area size, mutual position and contact condition of the contact interface between the butterfly plate and the valve seat conical sealing pair are unknown in advance. It shows the characteristics of complex contact nonlinearity. In the numerical simulation of the sealing process of Wafer Ball Valve, the physical model of surface contact is adopted, and the two contact surfaces are divided into passive body a (target body) and automatic body b (contact body). Passive body a represents the valve seat sealing pair, and automatic body b is the butterfly plate sealing pair. A contact node on the automatic body can contact any point on the passive body (not necessarily a grid node), as shown in Figure 2. During the analysis, the relationship between the degree of freedom and the equivalence of deformation of the node on the automatic body when in contact with the passive body are studied [3], the contact boundary conditions are determined, and then the control equation of the entire contact system is established based on the variational principle of boundary deformation harmony and the Coulomb friction law. This nonlinear incremental equation needs to be solved iteratively. The program uses the updated Lagrange formulation to solve