[CCoE Notice] PhD Defense Announcement

[Khator, Suresh]

Ph.D. Defense
NUMERICAL INVESTIGATION
OF VAPOR BUBBLE INTERACTION WITH A SUPERHEATED WALL
Mohammad Wasy Akhtar
Department of Mechanical Engineering
July 15th, 2011 at 9:00 am
Heat Transfer and Phase Change Laboratory (N263-D)
Committee:
Dr. Stanley J. Kleis, Associate Professor, Chair of the Committee
Dr. D. Keith Hollingsworth, Associate Professor, Mechanical Engineering
Dr. K. H. Wang, Professor, Civil Engineering
Dr. Larry C. Witte, Professor, Mechanical Engineering
Dr. Ralph W. Metcalfe, Professor, Mechanical & BioMedical Engineering and Mathematics

Abstract
            Vapor bubbles, once formed at nucleation sites or released from injection points, may rise under buoyancy effects and slide against adjacent surfaces. In this problem, known as the "sliding bubble problem," a thin liquid microlayer can form between the bubble and the superheated wall, which can contribute to significant heat transfer enhancement.  In order to better understand the sliding bubble problem in terms of microlayer dynamics, large scale dynamics, and their relationship to heat transfer enhancement, a complete solution of the problem is needed.
            This work presents a full three-dimensional numerical simulation of vapor bubble interaction with an inclined superheated wall on an adaptive octree (tree) based grid structure. A robust phase change model was developed to include both liquid and vapor heat fluxes into the interface with heat flux dependent interface temperatures. The validated phase change model was then used to study the dynamics of a growing vapor bubble approaching an inclined heated plate including the bubble approach, wall interaction leading to the development of the microlayer and the initial sliding regimes. Evolution of the heat transfer measures including wall, wake and microlayer regions were quantified for a single vapor bubble interaction with a superheated wall.

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