Abstract

Numerous industrial applications and environmental phenomena are centered around bubble interactions at multi-fluid interfaces. These applications range from metallurgical processing to direct contact evaporation and solid shell formation. Environmental phenomena, such as bubble collisions with the sea surface microlayer and the collision of liquid encapsulated bubbles, were also considered as motivators for this work. Although the associated flow dynamics are complex, they play a vital role in governing the related application outcome, be it in terms of mass or heat transfer efficiency, bubble shell production rate, chemical reaction rate, etc. For this reason, a fundamental understanding of the fluid dynamics involved in the bubble interactions are required to aid in optimal system design. In this work, rigorous experimental work was supplemented by in-depth theoretical analysis to unravel the physics behind these bubble interactions.

The focus of the present work is to develop an improved understanding of bubble interactions at liquid-liquid and compound interfaces. Extensive testing has been carried out to identify and classify flow regimes associated with single bubble and bubble stream passage through a liquid-liquid interface. Dimensionless numbers were identified and employed to map these regimes and identify transition criteria. The extension of one identified regime, bubble shell formation, to the field of direct contact evaporation was considered through the development of a numerical model to predict bubble growth in an immiscible liquid droplet. Additional dimensional analysis was carried out for the characterization of bubble collisions at solid and free surfaces. Previously developed numerical models were employed to form the relationship between the appropriate dimensionless groups capable of characterizing such collisions. This relationship was then used to describe a practical method for predicting the radial film size formed during the collision. Finally, three numerical models were developed to predict the bubble motion and the spatiotemporal evolution of the film(s) formed during the collision of a bubble with a liquid-liquid, solid-liquid-liquid, and gas-liquid-liquid interface. These models were validated through additional experiments carried out for this work as well as from data found in literature.

Library of Congress Subject Headings

Bubbles--Dynamics; Liquid-liquid interfaces; Fluid dynamics--Mathematical models

Publication Date

4-9-2019

Document Type

Dissertation

Student Type

Graduate

Degree Name

Microsystems Engineering (Ph.D.)

Department, Program, or Center

Microsystems Engineering (KGCOE)

Advisor

Satish G. Kandlikar

Advisor/Committee Member

Michael Schertzer

Advisor/Committee Member

Kathleen Lamkin-Kennard

Campus

RIT – Main Campus

Plan Codes

MCSE-PHD

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