PREDICTION OF PRESSURE GRADIENT AND HOLDUP IN HORIZONTAL LIQUID–LIQUID SEGREGATED FLOW WITH SMALL EÖTVÖS NUMBER

Abstract

This experiment utilized two-phase oil-water flows in a 26.1 mm diameter horizontal steel pipe to investigate segregated flow pattern. Data on pressure gradient and in situ phase distribution were obtained to come up with different combinations of phase superficial velocities, which ranged from 0.05 to 0.96 m/s. For the current liquid–liquid system having a small Eötvös number, we focused on identifying the effect of the interfacial tension and wall-wetting properties. Direct observation showed that oil and water started to mix when mixture velocity was increased. Also, at higher mixture velocities wherein the flows of two phases were initially separated, the droplets of one phase appeared in the mixed layer with negligible thickness. A closure relationship, which describes the interfacial mass transfer between liquid phases, was introduced into the framework of the two-fluid model. The model predictions agree well with the measured data. Similarly, an approach performance was evaluated based on the experimental data reported in previous literature.