纳米SiO_2材料声子热输运的格子玻尔兹曼法模拟

Simulation on Phonon Heat Transport of Silicon Dioxide Nanomaterial by Lattice Boltzmann Method

根据德拜物理模型,采用格子玻尔兹曼方法(LBM)对纳米二氧化硅薄膜内的声子热输运特性进行了模拟分析,得到了薄膜内的温度响应特性;在此基础上,分析了其法向有效导热系数。计算结果表明,当努森数大于0.01时,薄膜边界处出现温度跳跃,呈现出明显的微纳米尺度传热特性;当薄膜厚度小于20nm时,减小厚度可使其有效导热系数迅速降低;当薄膜厚度大于20nm时,其有效导热系数趋于恒定。

Based on the Debye model, the Phonon heat transport in nanofilm of silicon dioxide was simulated by Lattice Boltzmann method （LBM）. The temperature distribution in silicon dioxide film was predicted by simulation to analyze the effective thermal conductivity. The calculated results show that the temperature slip phenomenon appears at the boundary when the Knudsen number Kn is larger than 0.01, which indicates the obvious microscale effect of heat conduction in the film. When the film thickness is less than 20 nm, its effective thermal conductivity descends sharply with the decrease of thickness. As the thickness is larger than 20 nm, however, the effective thermal conductivity tends to be constant.