OPTIMIZATION OF CONVERGENT ANGLE OF VENTURI METER FOR THE BEST COEFFICIENT OF DISCHARGE

Abstract

Computational Fluid Dynamics is a compelling technique for getting stream flow and anticipating how this flow will react to various limiting boundary conditions. With this learning, the focal point of this research is to apply computational fluid elements such as CFD to issues dealing with stream flow measurement/estimation in closed conduits such as pipes utilizing differential stream meter like the Venturi meter. After thorough research from the existing literature it was determined that the Convergent Angle of a standard Venturi Meter has not been optimised in the existing studies. In simple words, there is a lack of literature pointing out that value of CA, for which the coefficient of discharge has the highest value or pressure differential between two Venturi sections is the least. This became the focus of present study. The range given for a standard ASME Venturi CA is 20-22˚. However, for the sake of experimentation the range of 19-22˚ is taken into consideration in this study. More than 50 models were created and run in ANSYS FLUENT, which was used as a CFD tool. Three β ratios are taken into consideration here, that are 0.4, 0.5 and 0.6. An optimum value of CA, corresponding to each β is found by finding out the best coefficient of discharge (closest to 0.99) for each test value of CA. Another aspect explored in this research is the relationship of Reynolds Number and Coefficient of Discharge. The effect of Reynolds Number on Cd is observed. This is done with the integration of ANSYS and laboratory results. The results of this study yields a definite value of CA for each β value. Along with this, a positive gradient followed by a Re vs Cd curve has been well established through Fluent. This is also validated by laboratory results.