Numerical study on sealing performance after wear of plug valve during opening–closing process

Abstract

The failure of the plug valve seal may result in dangerous accidents in the production and transportation process of petroleum and chemical products. In the paper at hand, the operating life of the plug valve is studied in the opening–closing process. The adhesion wear between the sealing surface of the plug valve is numerically studied in micro-scale, and the contact force between the sealing surface is balanced with the internal flow field of the plug valve and the deformation force between the set screw and the spool. The internal flow field of the plug valve in opening–closing process is calculated by finite element method. The deformation coupling model between the set screw and the spool is built to analyze the structure and the mechanics of the plug valve. Then, a leakage identification algorithm based on auto-correlation function is implemented for analyzing contact stress of the plug valve's sealing surfaces after wear. Finally, taking plug valve F-2 ISO-STANDARD as an example, the force of turbulent flow field on the spool is calculated during the closing process. Results show, that while the maximum contact stress increases, the pressure decreases, and the displacement trajectory of spool increases. The operating life decreases by increasing the roughness of the spool sealing surface. The model proposed provides a new practical method to evaluate the operating life of the plug valve, which is a good guidance for the design of the valve.