Phonon transfer in irregular shapes is important for assessing the influence of shape effect on thermal transport characteristics of low-scale films. It becomes critical for evaluating the contribution of the scattering phonons to the phonon intensity distribution inside the film. Hence, the sub-continuum ballistic-diffusive model is incorporated to formulate the phonon transport in an irregular geometry of low-size film adopting the transient, frequency-independent, equation of phonon radiative transfer. The discrete ordinate method is used in the numerical discretization of the governing transport equation. It is demonstrated that the geometric feature of the film influences the phonon intensity distribution within the film material. The transport characteristics obtained from the Fourier and the ballistic-diffusive models are markedly different in their spatial and temporal behavior. This is true when the device sizes are of the same order of magnitude as the mean-free path of the heat carriers.

中文翻译：

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不规则几何形状中的瞬态、亚连续体、热传导

不规则形状的声子转移对于评估形状效应对小尺寸薄膜热传输特性的影响非常重要。评估散射声子对薄膜内声子强度分布的贡献变得至关重要。因此，采用亚连续弹道扩散模型来制定不规则几何形状的小尺寸薄膜中的声子传输，采用瞬态、频率无关的声子辐射传输方程。离散纵坐标法用于控制输运方程的数值离散化。证明了薄膜的几何特征会影响薄膜材料内的声子强度分布。从傅立叶模型和弹道扩散模型获得的传输特性在它们的空间和时间行为上明显不同。当设备尺寸与热载体的平均自由路径处于同一数量级时，情况就是如此。