Empirical correlation for predicting pressure gradients of oil-water flow with drag-reducing polymer

This study deals with development and evaluation of empirical correlation for predicting pressure gradients of oil-water flow after the addition of drag-reducing polymer. The experimental pressure gradient data used for the correlation were obtained from three different acrylic pipe diameters (30.6, 55.7 and 74.7 mm) at different inclination angles. The drag-reducing polymer (DRP) which was a water-soluble copolymer of polyacrylamide and 2-acryamido-2-methylpropane sulfonic acid, was injected at 40 ppm concentration into the water phase of the oil-water flow. The flow conditions of 0.4–1.6 m/s mixture velocities and 0.05–0.9 input oil volume fractions were imposed. The measured pressure gradient data after the addition of the DRP were used to develop a friction factor correlation as a function of mixture Reynolds number. The developed correlation when tested against the current and previously published experimental data showed a good performance. It also showed the best performance when compared with similar existing correlation and homogeneous model.