FLOW OF OIL-IN-WATER EMULSIONS THROUGH ORIFICE AND VENTURI METERS

The applicability of conventional orifice and venturi meters to monitor the flow rate of oil/water emulsions was investigated. The discharge coefficients were determined for various unstable and surfactant-stabilized oil-in-water emulsions using a single orifice and a single venturi. The oil concentration was varied over a wide range of 0-84.32 vol %. The metering results indicate that orifice and venturi meters are feasible flow measuring devices for emulsions. The usual calibration curves of discharge coefficient versus Reynolds number (obtained from single-phase Newtonian fluids) are valid for the stable emulsions, both Newtonian and non-Newtonian. In the latter case, one needs to use the generalized Reynolds number instead of the conventional one. The orifice and venturi discharge coefficients for the unstable emulsions tend to deviate from the single-phase curves at low values of Reynolds number although the agreement is good at high Reynolds numbers. Based on the experimental data, empirical expressions for the orifice and venturi discharge coefficients are given.