纳米尺度材料有效导热率的界面效应

Effect of boundary of effective thermal conductivity for nanoscale material

为了研究界面效应对纳米尺度材料内声子热输运的影响,利用格子波尔兹曼法模拟二维矩形结构二氧化硅纳米材料内声子热输运,模拟过程考虑了边界面散射对声子平均自由程的影响.结果表明,相对镜反射的情况,漫反射界面明显降低了纳米尺度材料的导热率,边界面存在界面效应;随着镜反射因子的减小,材料的有效导热率降低;提高纳米尺度固体材料界面的粗糙度,界面热阻增强,有助于降低导热率.

To study the influence of boundary effect on phonon heat transport in nanoscale material, the phonon heat transport in silicon dioxide material for rectangular geometry is simulated, in which the effect of boundary scattering on phonon mean free path is considered. The results show that the effective thermal conductivity in nanoscale material reduces more obviously for diffuse reflection than the case of specular reflection, and the effect of boundary exists at the boundary. The effective thermal conductivity reduces with the decrease of specularity factor. The increasing of boundary roughness in nanoscale material, which enhances the thermal resistance of boundary, is in favor of the reduction of the thermal conductivity.