Computation of flow through Venturi meters

The computational fluid dynamics (CFD) work on Venturi meters reported in this paper was part of a large project for Shell Exploration and Production to investigate the application of Venturi meters to gas flow measurement. The majority of the experimental findings were reported in 'Unpredicted behaviour of Venturi flowmeters in gas at high Reynolds numbers' presented in the 1996 North Sea Flow Metering Workshop. CFD has been used to model the flow through Venturi tubes and thereby gain understanding of how the discharge coefficient is affected by the vital parameters of diameter ratio, pipe Reynolds number and roughness. It has also been used to calculate the effect of manufacturing tolerance. The discharge coefficients obtained from the calibration of Venturi meters have been used to validate the CFD predictions. The CFD results have also been compared with experimental results from the 1950s and 1960s with surprisingly good agreement. This work forms the basis of further possible research using CFD on the effect of upstream and Venturi surface roughness on the performance of these meters. The knowledge gained on the effect of surface roughness may also be applicable to ultrasonic flowmeters. (author)