Date of Award


Document Type

Campus Access Master's Thesis

Degree Name

Master of Science in Chemical Engineering (MS)

Administrative Home Department

Department of Chemical Engineering

Advisor 1

Lei Pan

Committee Member 1

Michael Mullins

Committee Member 2

Caryn Heldt


Air bubble interaction with liquid/air or liquid/solid interfaces is a fascinating problem of fluid dynamics that has a noticeable application in various industries employing the separation of components like oil extraction or wastewater treatment. Air bubble motion and collision with the surface involve the following phases: the release of the air bubble in the bulk of the fluid and its rise, impacting on the interface and bouncing, formation of the thin liquid film of water, and attachment or sliding of the air bubble on the interface. Although advances in the experimental and modeling techniques enabled a significant increase in the number of studies conducted to understand better this microscale air bubble-interface interaction, various aspects of this phenomenon are still unknown. To achieve a better understanding of the air bubble impact, key affecting parameters involved in this process, including bubble distance from the capillary, bubble size, the inclination angle of the solid substrate, and hydrophobicity were identified. An imaging system based on the interferometry technique is developed to experimentally investigate these parameters. It is found that increasing the inclination angle results in an increase in air bubble sliding velocity and an increase in thin liquid film thickness. Bubble size also has a direct effect on sliding velocity and film thickness as for a larger bubble, larger velocity, and film thickness are obtained. As a result of the more significant impact of these parameters on air bubble sliding velocity, exerted shear stress on the surface also increases. The stability of the thin liquid film is also investigated for different levels of the plate’s hydrophobicity. It is observed that for super hydrophilic plates, the film is stable and no three phase contact (TPC) forms on the solid plate. Whereas, in the case of more hydrophobic plates treated by polymers, liquid film ruptures, and air bubble attaches to the solid plate.

Available for download on Wednesday, August 07, 2024