Effects of Inertia and Surfactants on the Motion of Drop Through Circular Tubes

A numerical and theoretical study of the motion of deformable drops in flow through circular tubes is proposed. This investigation incorporates the effects of finite inertia and surfactant impurities. A modified version of the continuum surface force (CFS) model is developed which accounts for the transport of insoluble surfactant in the deformed surface of the drop. The modified CSF model is used to obtain numerical solutions for the drop deformation and speed, as well as the additional pressure loss in the tube due to the presence of the drop. The drop shape and its velocity relative to the average velocity of the two-phase system are measured in vertical glass tubes wherein the motion of the drop through the tube is visualized, and then compared to numerical solutions. The results of the proposed study will enhance our understanding of the motion of drops in pipe flow. In addition, the development of the modified CSF model will allow the application of this model to the solution of other problems involving fluid-fluid interfaces.