微结构气体夹层的导热和辐射比较

气体夹层作为散热或绝热机构在微传感器、微驱动器等微器件中是经常出现的。通常认为,气体夹层的导热是微结构表面间热量传递的主要方式,而表面间的热辐射可以忽略不计。本文比较了不同尺度和温度下电介质材料表面间导热和辐射换热的相对强弱,发现当辐射表面间距离只有十几个纳米的时候,辐射换热会大大强于导热。根据不同尺度和温度下导热和辐射相对强弱的不同,对微结构中电介质材料表面间热传递的主要方式进行了划分。

COMPARISON OF HEAT CONDUCTION AND THERMAL RADIATION BY MICROSCALE GAS GAPS

Gas gaps are familiar heat transfer structures in micro-devices. In general, heat conduction by the gaps is the primary way of heat transfer between surfaces. In this paper we investigate the relative significance of heat conduction and thermal radiation on various scale levels and under different temperatures. It is found that thermal radiation will become the dominant way of heat transfer when the distance between surfaces gets to tens of nanometers. The heat transfer between surfaces under different distances and temperatures is divided in terms of the relative significance of heat conduction and thermal radiation.