年間 6 号発行
ISSN 印刷: 1940-2503
ISSN オンライン: 1940-2554
Indexed in
BUBBLE DYNAMICS DURING POOL BOILING UNDER MICROGRAVITY CONDITIONS
要約
A numerical tool has been developed over the last decade to study bubble dynamics and the associated heat transfer during nucleate pool boiling. The numerical model divides the domain of interest into micro- and macroregions. The microregion is the ultra-thin liquid layer that forms between the advancing or receding vapor−liquid interface and the solid wall. The macroregion is the vapor−liquid occupied region away from the heated wall and excluding the microregion. Lubrication theory is used for the solution of the microlayer. Complete conservation equations of mass, momentum, and energy are solved in the macroregion. A level set function is used to capture the evolving, merging, and breaking interfaces. Gravity is an important variable of the problem. Experiments at earth normal gravity, reduced gravity in the parabolic flights, and microgravity conditions on the International Space Station are used to validate the numerical results. The reduced gravity is shown to increase the length and timescales of the process. Although bubble dynamics and vapor removal processes (except the bubble size) remain the same down to one-hundredth of earth normal gravity, there is a significant change in the vapor removal pattern under microgravity conditions.
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Dhir Vijay K., Advances in Understanding of Pool Boiling Heat Transfer—From Earth on to Deep Space, Journal of Heat Transfer, 141, 5, 2019. Crossref