Abstract The existing phonon Monte Carlo (MC) for ballistic-diffusive heat conduction are limited to small and simple structures owing to the huge time cost following with the increasing scale. This article presents a new hybrid phonon Monte Carlo-diffusion method for ballistic-diffusive heat conduction, which successfully characterizes the ballistic effect with significantly reducing the computational cost. Based on the idea that the phonon-boundary scattering mainly affects the regions adjacent to the boundaries when the system is considerably large, the whole system is divided into three zones: the boundary MC zone and the middle diffusion zone, between which is the overlap zone. By using an alternating method and setting virtual phonon bath or specular reflection as the boundary condition for the MC zones, the results of the phonon tracing MC and diffusion equation can be coupled and converge at the overlap zone. To verify, the cross-plane and in-plane film heat conduction, where slip boundary conditions are the major characteristics of the ballistic-diffusive regime, are simulated by the hybrid method as well as standard phonon tracing MC which works as a benchmark. It is found that the hybrid method can accurately predict the distributions of temperature and heat flux in the system with nearly the same precision as the phonon tracing MC while the computation time can reduce up to 90%, validating its potential use for larger and more complex structures.

中文翻译：

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用于纳米和微结构弹道扩散热传导的混合声子蒙特卡罗扩散方法

摘要 现有的弹道扩散热传导声子蒙特卡罗（MC）由于规模的扩大需要大量的时间成本，因此仅限于小而简单的结构。本文提出了一种新的用于弹道扩散热传导的混合声子蒙特卡罗扩散方法，该方法成功地表征了弹道效应，并显着降低了计算成本。基于声子边界散射在系统相当大时主要影响边界附近区域的思想，将整个系统分为三个区域：边界MC区和中间扩散区，它们之间是重叠区. 通过使用交替方法并设置虚拟声子浴或镜面反射作为 MC 区的边界条件，声子追踪 MC 和扩散方程的结果可以耦合并收敛于重叠区。为了验证，通过混合方法以及作为基准的标准声子追踪 MC 模拟了横向和面内薄膜热传导，其中滑移边界条件是弹道扩散机制的主要特征。结果表明，混合方法可以准确预测系统中的温度和热通量分布，精度与声子追踪 MC 几乎相同，而计算时间最多可减少 90%，验证了其在更大和更复杂的应用中的潜在用途。结构。其中滑动边界条件是弹道扩散机制的主要特征，通过混合方法以及作为基准的标准声子追踪 MC 进行模拟。结果表明，混合方法可以准确预测系统中的温度和热通量分布，精度与声子追踪 MC 几乎相同，而计算时间最多可减少 90%，验证了其在更大和更复杂的应用中的潜在用途。结构。其中滑动边界条件是弹道扩散机制的主要特征，通过混合方法以及作为基准的标准声子追踪 MC 进行模拟。结果表明，混合方法可以准确预测系统中的温度和热通量分布，精度与声子追踪 MC 几乎相同，而计算时间最多可减少 90%，验证了其在更大和更复杂的应用中的潜在用途。结构。