Multiphase drag reduction: Effect of eliminating slugs

Two-phase pressure drop measurements were taken for air/water mixtures in a 0.052-m diameter horizontal pipe with special focus on the superficial liquid velocity range of 0.03–1.2 m/s at superficial gas velocities of 3.8, 5.2, and 6.6 m/s. It was found that the addition of 400 ppm of sodium dodecyl sulfate (SDS) to the water reduced the pressure drop by 25–40% when compared to equal flow rates without SDS. The pressure drop reduction occurred where the SDS eliminated the occurrence of the intermittent flow present with water. It was also found that the same concentration of SDS had virtually no effect on single phase liquid pressure drop. The pressure drop reduction appears to be due solely to the suppression of intermittent flow patterns.