Performance Characteristics of Pipe Bends As Metering Devices for Oil/Water Mixtures

摘要

The applicability of pipe bends as metering devices for two-phase oil/water emulsions was investigated. The discharge coefficients were determined for emulsions over a wide range of oil and water concentrations. At low oil concentrations, the emulsions were of oil-in-water (O/W) type. However, at high oil concentrations, the emulsions were of water-in-oil (W/O) type. The inversion point was detected by an in-line conductance cell. A sharp change in the electrical conducance occurred upon inversion of one type of emulsion to another. Three standard long radius elbows with different dimensions and radii of curvature were tested. The results indicate that the single-phase calibration curves (discharge coefficient versus velocity) can be used to predict the flow rate of two-phase oil/water mixtures provided that the mixtures are well-homogenized. There is no observable difference between the discharge coefficients of oil-in-water and water-in-oil emulsions. The measured values of the discharge coefficients for emulsions are reasonably close to the values predicted from the equations proposed in the literature for single-phase fluids.