粗糙表面接触热阻的分形描述

Fractal Description of Thermal Contact Resistance between Rough Surfaces

空间制冷系统对精密探测元件的冷却是通过固体接触导热实现的,在真空低温环境下,它的冷却效果取决于界面的接触热阻.为了研究真空下接触界面的传热机理及其影响因素,采用Cantor集分形理论对固体粗糙表面的拓扑形貌进行了描述,基于固体的弹塑性理论解决了塑性守恒条件下的表面粗糙度在法向载荷作用下的变形问题,推导出基于分形理论的递归接触热阻网络模型理论.同实验数据的比较表明,理论计算和实验结果吻合良好,该模型能较好地描述接触界面的传热现象.

Complex scientific instruments such as space infrared telescope facilities in satellite are often cooled through bolted or pressed links to their refrigeration systems. Its cooling effect depends directly on the interface contact resistance. In order to study the mechanism and influence factors of heat transfer, the nature of thermal contact resistance between rough surfaces was analyzed. The topography of rough contact surfaces was described with Cantor set fractal theory. And an elastic-plastic theory was developed to obtain the deformation of surface asperities where the volume conservation of plastically deformation is considered. Finally, the recursive tree thermal contact resistance model based on the Cantor set fractal theory was obtained. And the numerical results of theoretic formulation agree with the experimental results and the fractal model based on the Cantor set theory can predict TCR phenomenon well.