Numerical Research on the Sealing Performance of Plug Valve Based on Microscopic Contact Mechanics

In this paper, taking the plug valve as the research object, the deformation coupling model between the set screw and the cock is established by analyzing the structure and the mechanics of the plug valve. A leakage identification algorithm for the plug valve's sealing surface is established by analyzing contact stress of the plug valve's sealing contact surfaces which are constructed by auto-correlation function. Taking plug valve F-2 ISO-STANDARD as the research object, the variation of contact stress of the sealing surfaces is numerically studied with change of the number of tightening cycles of the set screw in the installing process, and then the sealing performance of the plug valve is studied numerically. Results of numerical study show that with the increase of the number of tightening cycles of the set screw, the contact area of the sealing surfaces increases, while the area of the leakage path gradually decreases, and the maximum contact stress of sealing surfaces increases at the stage of the initial sealing with the increase of sealing surfaces' roughness. With the increase of the fluid pressure in the plug valve pipe, the minimum cycle number of tightening, cock compression force and the maximum contact stress of the sealing surface increase at the stage of the initial seal contact. This research provides a new method for the study and application of the plug valve sealing.