Design and Modelling of a 90-Degree Ball Valve with a Linear Pressure Drop

摘要

Globe valves also known as ball or gate valves are used to control fluid flow in a vast number of applications. Most of the existing applications use them because of their simplicity and very low cost. However, these valves are known for their poor precision for controlling the flow and the lack of electromechanical means for their actuation. Moreover, because of their low linearity their use in closed loop control applications make them nearly unusable. The goal of this research project was to investigate means for redesigning the metering area of a ball valve in such a manner that the pressure vs. flow characteristic would be close to a linear trend. Two different profiles where designed and tested experimentally and modelled using CFD techniques for the estimation of their valve flow coefficients. The model was able to accurately predict the behaviour of the valve with less than a 10% error when fully open. The model can be used for scaling the size of the ball for larger applications and for tuning controlling strategies for flow dispensation in real life applications.