Optimization of Biporous Micropillar Array for Enhanced Heat Transfer Performance
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v08bt10a002-imece2015-52651.pdf
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Author(s)
Wei, Mengyao
Somasundaram, Sivanand
He, Bin
Liang, Qian
Raj, Rishi
Tan, Chuan Seng
Wang, Evelyn N.
Date Issued
2015
Journal
Volume 8B: Heat Transfer and Thermal Engineering
Publisher
ASME International
Citation
Wei, Mengyao, Sivanand Somasundaram, Bin He, Qian Liang, Rishi Raj, Chuan Seng Tan, and Evelyn N. Wang. “Optimization of Biporous Micropillar Array for Enhanced Heat Transfer Performance.” Volume 8B: Heat Transfer and Thermal Engineering (November 13, 2015). doi:10.1115/imece2015-52651.
Version
Final published version
Abstract
© Copyright 2015 by ASME. Biporous evaporator wicks for heat pipe and vapor chambers can perform superiorly by reducing the viscous drag with larger pores or channels and simultaneously generate higher capillary pressure with smaller pores radius. Unlike conventional sintered metal biporous wicks, cylindrical silicon micropillar based evaporator with microchannels, possess the following advantages: mature and easily controllable fabrication process, possibility of direct integration with semiconductor devices and no risk of thermal expansion mismatch. In this work, we investigated a biporous wick for the evaporator design, which consists of micro pillar arrays interspersed within micro channels. This design was systematically studied by constructing a mathematical model, by coupling Brinkman's equation with mass and energy conservation equations, to predict the biporous wicks' heat transfer performance. In order to find the best combination of geometric factors that give the highest heat flux at a certain superheat value, optimization in Matlab was done. The effect of diameter to pitch ratio, aspect ratio, channel width and contact angle on wick's permeability, capillary pressure and evaporative heat flux were also investigated. Conclusion was drawn that a higher diameter to pitch ratio of 0.57, reasonable aspect ratio of 1.75∼3.22, island to channel width ratio of around 1.96 are preferred in this kind of biporous wick's design. Biporous wick show potential to dissipate heat flux of 515.7 W/cm2 at superheat of 40 °C, which is 134 % higher compared to monoporous wick.
MIT Department
Singapore-MIT Alliance in Research and Technology (SMART)
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1115/IMECE2015-52651
