(Drs. William Black and James Hartley, co-advisors)

"Analysis of Vibration Induced Droplet Atomization for High Heat Flux Evaporative Cooling"

Abstract

Current predictions suggest that thermal dissipation for high-performance microprocessors will approach 160 W, with regional surface heat fluxes that exceed 100 W/cm2. To dissipate such high heat fluxes, at prescribed operating temperatures, more aggressive means of thermal management than traditional fan-heat sink combinations will be essential for continued development of high-power computers. One solution for effective thermal management of microprocessors is to use the high heat transfer coefficients that result from two-phase heat transfer. Through boiling and condensation, two-phase heat transfer enables the dissipation of high heat fluxes at low temperature differences. The advantages of two-phase heat transfer have been incorporated into devices such as heat pipes that have been successfully used to cool electronic devices for a number of years.

As an alternative method to heat pipes for dissipating heat in high heat flux applications, vibration induced droplet atomization (VIDA) has also proven to be a viable thermal management technology. Its successful implementation into heat transfer cells has been recently established, but due to a lack of understanding of the VIDA process, cell design methods are based mostly upon experience. Therefore, future development of VIDA heat transfer cells would benefit from a better understanding of the fundamental fluid mechanics and heat transfer principles that govern the operation of a VIDA-based thermal management cell. The objectives of this proposed research are to determine the variables that most influence the onset of VIDA in a liquid layer, to develop correlations to predict the onset of VIDA in that layer, and to develop an analytical model for the heat transfer that occurs inside a VIDA cell.