Flow resistance optimization of link lever butterfly valve based on combined surrogate model

Large-diameter link lever butterfly valve is widely used in the transportation and adjustment of fluid media in the marine field. Because the opening and closing process of the link lever butterfly valve is mainly realized by the internal connecting rod mechanism, and it always exists in the fluid domain to affect the flow performance of the valve. It is necessary to optimize the connecting rod mechanism inside the valve. There are many structural safety problems in the connecting rod mechanism during the valve opening and closing process, such as large starting torque, vortex and turbulence near the valve disc causing resonance of the device, etc. This paper proposes a method to optimize the internal structure of the link lever butterfly valve to improve the flow performance of the valve while meeting the structural safety. The surrogate model is combined with finite element method (FEM) and computational fluid dynamics (CFD) analysis to improve optimization efficiency. The Response surface method (RSM) model is used to replace the Kriging model with insufficient accuracy, and build the combined surrogate model based on the global error criterion. The optimization algorithm combined with MIGA and NLPQL is used to obtain the best results of internal structural variables. The accuracy of the combined surrogate model is verified through FEM and CFD analysis. The results show that the flow performance of the link lever butterfly valve is greatly increased and combined surrogate model can effectively replace the finite element model to solve the optimization problem.