Date of Graduation

2016

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

John M Kuhlman

Committee Co-Chair

Patrick Browning

Committee Member

Christopher Griffin

Abstract

The main objective of this thesis is to study the characteristics of bubbles in pool boiling under microgravity conditions with and without the influence of a magnetic field. In order to create microgravity conditions, the parabolic path of an aircraft was used for a period of 20-30 seconds, during which time the experiment was conducted. Two cylindrical tanks were used for the boiling process in the experiment. One tank had a permanent magnet attached at the bottom, and the other one was kept as the control. MnCl2 was dissolved in distilled water to make a paramagnetic liquid, and which used in the pool boiling process. The experiment was captured on video simultaneously from two different angles, and later analyzed frame by frame using image processing techniques to obtain the bubble characteristics during the different stages of the boiling process. During this investigation of bubble motion, two main studies were conducted. First, the characteristics of a single bubble were studied, such as: center of the bubble, shape of the bubble (maximum radius and minimum radius in vertical and horizontal direction), vertical and horizontal displacement of the center of the single bubble, rate of change of the position of the bubble coordinates and the vertical component of the selected single bubble velocity. Second, the motion of the bubbles was studied, including the directionality, the velocity and the fluctuation of the size and shape of the bubble was studied. The results from the study revealed that as the strength of the magnetic field reduces, the influence of the magnetic field on bubbles was weakened along the vertical axis of the tank. This phenomenon was visualized graphically with various bubble metrics.

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