کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
659734 | 1458137 | 2009 | 8 صفحه PDF | دانلود رایگان |
Advent of micro thermal devices such as lab-on-a-chip and micro heat pump necessitates development of highly effective insulation chips or layers. This paper reports the development of a vacuum insulation chip (VIC) having very low effective thermal conductivity and very small thickness. Fifty nanometer thickness metal coating on both sides of an LCD glass chip and 5 μm vacuum gap are stacked in a series to decrease the heat transfer by radiation. An array of support legs is necessary to maintain the structure under the atmospheric pressure. Design of VIC involves trade-offs between the heat conduction through the multi-layer structure and the mechanical strength. A model to determine the actual design values is proposed. The results are in reasonable agreement with the more refined results using commercial numerical codes. Based on these results, a VIC of 32 × 32 × 1.88 mm3 is manufactured, and the effective thermal conductivity is measured by guarded hot plate method. The chip shows effective thermal conductivities of 0.0015 and 0.001 W/m K at vacuum levels of 1.33 and 0.24 Pa (N/m2), respectively.
Journal: International Journal of Heat and Mass Transfer - Volume 52, Issues 5–6, February 2009, Pages 1276–1283