We report the modeling of a novel approach to passive heat transfer from electronic equipment through an enclosure wall with built-in vertical channels. This passive cooling method is based on the different temperature requirements between the enclosure surface and the internal heat-generating devices. This approach takes advantage of natural convection, known as the chimney effect, resulting from higher temperatures in vertically oriented channels. In addition to channel convection, the skin surface exposed to the environment dissipates the heat passively by both natural convection and radiation. The configuration of the wall and channels, termed a Channel-Composite-Wall (CCW), creates a novel form of passive cooling that we have analyzed and modeled. The inner side of the CCW is assumed to be uniformly heated. The three-dimensional flow regime is observed by means of PIV (particle image velocimetry) experiments and numerical studies. The unique velocity profile inside each channel is observed and can be regarded as similar to the flow in the differently heated parallel plates. The channel flow is modeled by breaking the channel down into two sections plus the exposed skin wall. Based on these observations, the relationship between the internal flow field and external convective flow can be considered to be handled separately. The thermal characteristic is also studied based on the correlations. The thermal conductivity and thickness of the solid partition of channels are found to be significant contributors to performance. The analytic model of the CCW was verified by numerical calculations and experiments. The model reasonably closely expresses the characteristics of this comprehensive conjugate heat transfer. The model can thus be used for the development of passively cooled electronics enclosure.

1.
Semiconductor Industry Association, International Technology Roadmap for Semiconductors 2004 update, 2003 SIA road map, (2004)
2.
Yazawa K., “E Natural Convection Enhancement of Channel Array in Conjunction with wall surface”, Proceedings of ITherm2004, pp 128–133, IEEE (2004)
3.
Iwasaki, H. and Ishizuka, M., “Natural Convection Air Cooling Characteristics of Plate Fins in a Ventilated Electronic Cabinet”, Thermal Science & Engineering, Vol. 8 No. 1, HTSJ (2000)
4.
Coxe, W. K., Solbrekken, G. L., Yazawa, K. and Bar-Cohen, A., Experimental Modeling of the Passive Cooling Limit of Notebook Computers”, Proceedings of ITherm2002, IEEE (2002)
5.
Solbrekken, G. L., Coxe, W.K., Yazawa, K. and Bar-Cohen, A., “Passive Cooling Limits for Ventilated Notebook Computers”, Proceedings of the 12th International Heat Transfer Conference, (2002)
6.
Yazawa, K., Nishino, Y., Nakagawa, S. and Ishizuka, M., “Experimental Validation of Channeled Wall Passive Cooling Enhancement”, Proceedings of InterPACK2005, IPACK2005–73078, ASME (2004)
7.
Elenbaas
W.
, “
The Dissipation of Heat by Free Convection: The Inner Surface of Vertical Tubes of Different Shapes of Cross-Section
”,
Physica
(
IX
/
8)
, pp
865
874
, (
1942
)
8.
Shah, R. K., and London, A. L., “Laminar Flow Forced Convection in Ducts”, Advances in Heat Transfer, (1978)
9.
Churchill, S.W., and Chu, H.S., “Correlating Equations for Laminar and Turbulent Free Convection From a Vertical Plate”, International Journal of Heat and Mass Transfer, Vol. 18, (1975)
10.
The Visualization Society of Japan, The PIV Handbook, Morikita Shuppan, pp 1–11, (2002)
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