Analysis Of Wear Mechanism And Flow Field Simulation On The Opening And Closing Process Of The Gate Valve

Gate valve is the major control unit of the oil-gas wellhead equipment. And its performance is directly related to the reliability of wellhead equipment and the safety of drilling and construction. Phenomena such as vibration, noise and internal and external leakage occur during the opening and closing process of wellhead gate valve under high temperature and pressure. Wear and corrosion with various degrees of appear on the valve plate, valve seats and the inner surface of the valve body. Many phenomena as the expansion of the valve plate hole, valve seat wear and stress crack also exists, even the valve body piercing in some individual circumstance.Combined with the actual drilling conditions, the erosion mechanism of the metal surface in the fluid carrying suspended solid particles and wear mechanism of the metal in H2S, CO2 environment was analyzed using the theory of friction Hutchings. The analytical results show that the combinations of the variety of wear and corrosion wear lead to the rapid wear of the gate valve.The fluid dynamics mass conservation equation and momentum equation in the continuous, incompressible, constant viscosity pipe was built, and the geometrical model of the gate valve flow channel was also built. Based on the theoretical analysis FLUENT the numerical simulation of fluid dynamics software was used to complete the simulation analysis. The k-εtwo-equation eddy viscosity models based on the average Reynolds was chosen to carry out the numerical simulation with the boundary conditions accord with the actual working conditions The gate valve velocity and pressure field of the gate valve was obtained. Previous theoretical results are accordant with the present simulation results. It shows that the numerical analyses are reliable.Finally, the internal flow field and the rapid wear mechanism of the gate valve were analyzed. The analytical results show that the local high-speed low-voltage is the root cause of the gate valve's rapid wear. Based on analysis, the gate valve structure was improved. The flow field numerical simulation of the improved structure was carried out. Its result validates that the improved structure can reduce the direct impact of the fluid speed of the over-current cross-section on the gate valve to a certain extent.