声子水动力学和Ziman区瞬态导热MC模拟研究

Phonon Monte Carlo Simulations for Transient Heat Conduction in Phonon Hydrodynamics and Ziman Regimes

热波现象揭示出热量传递过程的波动性,对该现象的研究有助于增进对瞬态导热机理的认识。本文基于Callaway双弛豫时间近似模型,利用散射概率的概念,发展了解决R散射与N散射耦合的声子蒙特卡洛(MC)模拟方法,对处于声子正规散射主导的声子水动力学区域的热波现象和声子Ziman区域的导热现象进行了研究。研究指出,热波的基础是声子传递过程中的动量守恒,并发现,定向的边界条件与Lambert边界条件相比较,可以更为集中地传递能量,而随着散射概率的增加,R散射的影响逐渐增强,声子导热由水动力学导热模式过渡到扩散导热模式。

Thermal wave implies the wavelike behaviors in heat transfer,which promotes a better understanding of heat transport mechanism.In the paper,a phonon Monte Carlo simulation method is developed based on the Callaway’s dual relaxation time approximation model and the concept of scattering possibility,to solve the coupled problem of normal process scattering and resistive process scattering.Then the thermal wave based on phonon hydrodynamics and phonon Ziman regime heat conduction phenomena are studied.It reveals that thermal wave occurs because of the momentum conservation.The directional boundary condition can emit a more concentrated energy package than Lambert boundary condition.The phonon hydrodynamic phenomena change into the diffusion heat conduction phenomena with the enhancement of R process,influenced by the increase of scattering possibility.