| This thesis involves a study of the behavior of bubbles in dilute surfactant solutions. The focus of the thesis is on the unsteady motion of bubbles. It is well known that the steady-state rise velocity of bubbles smaller than about 5mm is significantly smaller in dilute surfactant solutions than in pure water. The dissolution rate of soluble bubbles can be an order of magnitude smaller in dilute surfactant solutions. These phenomena are of practical interest in mass transfer operations such as the oxygenation of bioreactors and froth flotation systems. However, it was only recently realized that insoluble bubbles can reach a maximum velocity that is close to the steady-state velocity in pure water before slowing down. This suggests that the surfactant sorption kinetics are sufficiently slow that they can significantly affect the behavior of bubbles in situations of practical interest. One might also expect that sufficiently soluble bubbles may dissolve at the same rate in dilute surfactant solutions as they would in pure water. A goal of this thesis was to test the above ideas using a combination of numerical simulations and experimental simulations. |
