Abstract

The continuous development of microelectronic industry and miniaturization of microchips has led to a demand for large amount of heat removal from their surface. Conventional cooling systems are unable to extract such large amount of heat and thus necessitating efficient thermal management. Pool Boiling provides a highly efficient way to remove high heat at low wall superheats. Enhancement of heat transfer by pool boiling will result in reduced size and better efficiency of the device. The current research work focuses on the application of enhanced heat removal technique by macro-convection mechanism using an air injection system. Air injection through the heated wall is hypothesized to provide significant heat transfer enhancement like the convective component in pool boiling. The stirring action of bubbles is expected to provide heat transfer enhancement by corresponding transient conduction and microconvection mechanisms. Experiments are conducted in a pool of water at atmospheric pressure with air injected through multiple nozzles over a superficial velocity range of 0.04 to 0.15 m/s over a 10 mm square heated copper surface. The latent heat transfer component is kept low to reduce evaporation of water in the air stream by lowering the bulk temperature. Heat transfer coefficients in the range 6.8 -13 kW/m2 °C were obtained with a superficial air velocity of 0.04-0.15 m/s. Using a jet impingement model for the returning liquid to the heater surface, the theoretical estimated heat transfer coefficients are found to be within 30% of the experimental values. The results from this work can be used for enhancing single-phase liquid cooling of high-powered electronic devices as well as other practical systems.

Library of Congress Subject Headings

Heat sinks (Electronics); Ebullition; Heat--Transmission

Publication Date

3-2021

Document Type

Thesis

Student Type

Graduate

Degree Name

Mechanical Engineering (MS)

Department, Program, or Center

Mechanical Engineering (KGCOE)

Advisor

Satish Kandlikar

Advisor/Committee Member

Michael Schertzer

Advisor/Committee Member

Robert Stevens

Campus

RIT – Main Campus

Plan Codes

MECE-MS

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