Effects of a Surfactant on the Motion of a Confined Gas-liquid Interface. the Influence of the Péclet Number

Abstract

The displacement of a liquid initially contained in a capillary tube or between two closely spaced parallel plates by a gas phase, is largely affected by the presence of a soluble surfactant. The distribution of the surface active solute within the bulk and along the interface depends on the relative strength of convection, diffusion and the kinetics of adsorption/desorption. In this work, a complete description of the velocity and concentration fields in the bulk and along the interface is presented for several values of the Péclet number. The influence of this parameter on the film thickness is also analyzed.