Pipeline flow of unstable and surfactant‐stabilized emulsions

Abstract

Abstract The literature available on pipeline flow behavior of emulsions is reviewed critically. New results concerning the laminar and turbulent flow behaviors of unstable (without any added surfactant) and surfactant‐stabilized water‐in‐oil emulsions are presented. The unstable emulsions exhibit drag reduction behavior in turbulent flow; the measured friction factors fall well below the values expected on the basis of the laminar flow properties. Unstable water‐in‐oil emulsions exhibit much stronger drag reduction activity than the unstable oil‐in‐water emulsions. The drag reduction activity diminishes (in some cases vanishes completely) upon the addition of a surfactant to the system.