Author

Ankit Kalani

Abstract

The growing trend in miniaturization of electronics has generated a need for efficient thermal management of these devices. Boiling has the ability to dissipate large quantity of heat while maintaining a small temperature difference. Vapor chamber with pool boiling offers an effective way to provide cooling and maintaining temperature uniformity. The objective of the current work is to investigate pool boiling performance of ethanol and FC - 87 on microchannel surfaces. Ethanol is an attractive working fluid due to its better heat transfer performance and higher heat of vaporization compared to refrigerants, and lower boiling point compared to water. The saturation temperature of ethanol can be further reduced to temperatures suitable for electronics cooling by lowering the system pressure. Fluorocarbons are considered to be ideal fluids for electronics cooling due to their low normal boiling point, dielectric and inert nature. FC - 87 is selected for the current work. Ethanol is tested at four different absolute pressures, 101.3 kPa, 66.7 kPa, 33.3 kPa and 16.7 kPa using different microchannel surface configurations. Heat dissipation in excess of 900 kW/m2 was obtained while maintaining the wall surface below 85 °C at 33 kPa. Flammability, toxicity and temperature overshoot issues need to be addressed before practical implementation of ethanol-based cooling systems in electronics cooling application. FC - 87 with microchannel yields average performance when compared to literature. Effect of surface area is identified as the key reason for performance enhancement. A new finned structure is developed, which gave a heat flux value 1.25 MW/m2 at 40 °C wall superheat for FC - 87 at atmospheric conditions.

Publication Date

7-30-2012

Document Type

Thesis

Department, Program, or Center

Mechanical Engineering (KGCOE)

Advisor

Kandlikar, Satish

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in December 2013.

Campus

RIT – Main Campus

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