Optimization of an Eccentric Check Valve

Abstract

A butterfly valve, which is a rotating disk, is used to open and close a pipeline, and control the flow rate at relatively low pressure. The eccentric check butterfly valve that has an eccentric rotating axis. it is use not only as a butterfly valve to control the flow rate or pressure, but also as a check valve to prevent reverse flow. The eccentric check butterfly valve is light, occupies a small space and rotates fast because the rotating axis of the disk is located eccentrically from the central axis. An optimization problem with a characteristic function is formulated to determine the amount of eccentricity. The characteristic function to be minimized is defined for the stability of the flow filed. The maximum resultant pressure of the valve disk is calculated by waterhammer analysis when the flow stop suddenly. Structural analysis carried out to evaluate the maximum resultant pressure of the valve disk and structural safety. Structural optimization is performed considering the structural safety and the stability of the flow field. The process of structural optimization has two steps: topology optimization and shape optimization. Mass distribution of the disk housing is determined using topology optimization. The stiffness of the disk housing is enhanced with respect to the maximum pressure. since toptlogy optimization does not give the final dimensions, shape optimization is utilized to determine the details based on the results of topology optimization. The objective function of shape optimization is the mass of the valve disk while constraints are imposed on stresses of the valve disk. The stress constraints are related to the structural safety. At the optimum, stability of the flow field is evaluated again. A light design is derived to satisfy the structural safety and the stability of the flow field. FLUENT is used for fluid analysis and GENESIS is used for structural optimization.