Experimental and Numerical Study of Basic Discharge Coefficient (Cd) For Orifice Plate Meters Under Single Phase Fluid Flow

Orifice meter’s accuracy is of great importance in fluid flow metering due to the monetary value of fluid transferred daily. The discharge coefficient of the orifice meter calculate for the irreversible losses in the system, which requires extensive experimental validation in accordance with the API standard. This paper presents the numerical simulation study as an alternative of experimental works for estimating the orifice plate’s discharge coefficient. In this study, numerical simulations performed under several orifice diameters with single-phase gas flow with multiple gas flow rates. Two different Reynolds Averaged Navier-Stokes turbulent models, i.e., SST k-ω and Realizable k-ℇ model, are employed to solve the upstream and downstream orifice differential pressure, based on which the corresponding discharge coefficient is generated. Experimental data points are employed to validate the numerical study, and its comparison studied statistically. Simulations of two orifices display in this study, i.e., 1-inch orifice with SST k-ω and 1.5-inch orifice with Realizable k-e turbulence model. It observed that the pressure increases slightly as the fluid approaches the orifice, and the pressure drops suddenly and continues to drop until it reaches the vena contracta. Moreover, due to the increased velocity of the gas passing through the reduced area of the orifice, the pressure gradually increases afterward. Compared with the experimental data, the numerical simulation under-predicts the discharge coefficient. However, the data discrepancy is less than 4% and 6% respectively. The pressure at 12-inch downstream of the orifice is obtained to investigate the pressure loss ratio. The pressure loss ratio is slightly over-predicted by the numerical simulation of 2% and 6% relative error respectively. Furthermore, user-defined functions that consider the effect of the turbulence model can be developed based on the contribution of this study to expand the numerical