Abstract

Heat generation in electronic hardware has become a major limiting factor in achieving maximum efficiency in modern computer parts. Classically forced flow convection systems are used to remove this heat at high rates but can be costly to implement and can take up space that may be needed for other critical components. In response to this, systems that use fewer parts scale in compact spaces are needed. In these situations, pool boiling as a heat transfer mechanism can excel. Pool boiling removes heat through the evaporation of fluid. On a flat surface pool boiling is chaotic and this random nature may hinder its ability to remove heat as effectively. The surface geometry of a pool boiling system can be altered to direct the flow of generated vapor bubbles to allow for increased heat flow and higher heat transfer performance. By creating paths for the vapor to follow we can induce currents in the flow of cool fluid to the heater surface, creating a faster cycle of vapor production therefore cooling the heated surface at a faster rate.

The purpose of this study is to investigate angled chip notches as an alternative to already existing high heat transfer surfaces in pool boiling. These alternative chips may prove cheaper or easier to produce the alternative which may incorporate fine, hard to produce features or post process coatings like sintering and the addition of hydrophobic materials. This study will examine the effect these specifically designed notches have on the interaction between the directed vapor and the liquid pathways they create. By creating notches in the surface of the chip, vapor bubble is given sites to nucleate and form vapor pathways. The angle walls on the one side of the notch will act as a wedge when water being driven toward the notch pushes the nucleating bubble up and out of the notch. Combined with pairing nucleating notches up with another oppositely facing one the vapor bubble is departing earlier then it would have had it not been assisted by these surface elements. With just these paired notches placed in row, an HTC improvement of 158% was recorded, compared to a plain copper surface. With the inclusion of microchannels this improvement was brought up to 161%

Library of Congress Subject Headings

Heat sinks (Electronics); Fluid-structure interaction; Ebullition; Heat exchangers--Fluid dynamics; Nucleate boiling

Publication Date

9-2019

Document Type

Thesis

Student Type

Graduate

Degree Name

Mechanical Engineering (MS)

Department, Program, or Center

Mechanical Engineering (KGCOE)

Advisor

Satish G. Kandlikar

Advisor/Committee Member

Michael Schrlau

Advisor/Committee Member

Stephen Boedo

Campus

RIT – Main Campus

Plan Codes

MECE-MS

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