论文部分内容阅读
声子是介电固体中导热过程的主要载体,研究声子的黏性对正确预测纳米材料中的非傅里叶导热等现象有着重要意义.本文从热质理论出发,基于涨落耗散理论导出了声子气黏度的表达式:ηh=hv/3πλα,其中ηh表示声子气的黏度,v_a为声子平均频率,λ为声子波长,α为材料热扩散系数。预测了单晶硅在300 K时的声子气黏度,其参考值为4.8×10~(-9)Pa·s。并且与基于声子水动力学模型和气体动理论模型的声子气黏度结果进行比较,发现本文模型的结果比声子水动力学模型的结果大2个量级,而比动理论模型小5个量级。
The phonon is the main carrier of the thermal conduction in the dielectric solid, and studying the phonon’s viscosity is of great significance for the correct prediction of the non-Fourier thermal conduction in nanomaterials.In this paper, based on the theory of thermal dissipation, Ηh = hv / 3πλα, where ηh denotes the viscosity of phonon gas, v_a denotes the average phonon frequency, λ denotes the phonon wavelength, and α denotes the thermal diffusivity of the material. The phonon gas viscosity at 300 K was predicted with a reference value of 4.8 × 10 ~ (-9) Pa · s. And compared with the results of phonon gas viscosity based on phonon hydrodynamic model and gas kinetic model, it is found that the results of this model are two orders of magnitude larger than those of the phonon hydrodynamic model, but smaller than that of the kinetic model A magnitude.