微尺度下壁面粗糙度对面向导热影响研究

THE INTERFACE ROUGHNESS EFFECT ON THE IN-PLANE THERMAL CONDUCTIVITY IN NANOSCALE

随着空间尺度的缩小,界面对导热的影响就会越来越明显。本文采用非平衡分子动力学模拟方法模拟了壁面的粗糙度对面向导热的影响,并给出微尺度下的粗糙度定义。在模拟中构造了不同的壁面粗糙度,得到了面向热导率随着壁面粗糙度增加而减小的结果。分析认为壁面的镜面反射率随着粗糙度增加而减小,而镜面反射率减小将导致热导率下降．

With the shrink of spatial criterion, the influence of interface roughness is more and more obvious to the heat conduction. This work defined the surface roughness in nanosacle. Various interface roughness was structured to investigate how the thermal conductivity varied with changes of interface roughness using a non-equilibrium molecular dynamic （NEMD）. The result shows that with the increase of interface roughness the in plane thermal conductivity decreases. It is because that when the interface roughness increases the ratio of specular reflectivity of the phonons at interface decreases, and the thermal conductivity lessens as the ratio of specular reflectivity decreases.