Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Engineering Science

Program

Mechanical and Materials Engineering

Supervisor

Khayat, Roger E

2nd Supervisor

DeGroot, Christopher T

Joint Supervisor

Abstract

Bubble formation and dissolution have a wide range of industrial applications, from the production of beverages to foam manufacturing processes. The rate at which the bubble expands, or contracts has a significant effect on these processes. In the current work, the hydrodynamics of an isolated bubble expanding due to mass transfer in a pool of supersaturated gas-liquid solution is investigated. The complete scalar transportation equation (advection-diffusion) is solved numerically and it has been observed that the present model predicted an accurate bubble growth when compared with existing approximated models and experiments. The effect of gas-liquid solution parameters such as inertia, viscosity, surface tension, diffusion coefficient, system pressure, and solubility of the gas has been investigated. It is found that the surface tension and inertia have a very minimal effect during the bubble expansion. However, it is observed that the viscosity, system pressure, diffusion, and solubility have a considerable effect on bubble growth.

Summary for Lay Audience

The current thesis investigates the growth of a single bubble in a mixture of supersaturated gas-liquid solution. A solution is said to be supersaturated when the amount of gas dissolved in the solution is more than it can hold. The growth and control of bubbles play a key role in industrial applications such as bubble column reactors where gas is dissolved in the liquid in terms of bubbles, daily consumable beverages where CO2 is suspended as bubbles, manufacturing processes where thermoplastic foams are produced using blowing agents, and in marine commutators where the collapse of high-pressure bubbles causing damage to propeller blades of the ships. In the literature, the governing equation which describes the concentration of gas in the liquid is solved with many underlying assumptions and simplifications. In the present study, this complete equation is solved numerically and compared with the existing theory and experiments. The present numerical approach is validated by reproducing the results in the literature. It has been depicted that the present theory matched closely with the experiments than the existing theories.

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