Multiscale solutions of radiative heat transfer by the discrete unified gas kinetic scheme
Multiscale solutions of radiative heat transfer by the discrete unified gas kinetic scheme
复制标题
离散统一气体动力学方案的辐射传热多尺度解
DOI：
10.1103/physreve.97.063302
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发表时间：
2018
影响因子：
2.4
通讯作者：
Tan He-Ping
中科院分区：
文献类型：
--
作者：
Luo Xiao-Ping;Wang Cun-Hai;Zhang Yong;Yi Hong-Liang;Tan He-Ping
辐射传递方程（RTE）有两个以光学厚度为特征的渐近区，即光薄区和光厚区。在光学薄态中，弹道输运或动力学输运占主导地位。在光学厚态中，能量输运完全由光子之间的多次碰撞控制；也就是说，光子通过扩散的方式传播。为了获得RTE的收敛解，传统的数值格式对空间网格的数量有很强的依赖性，这导致在扩散占主导地位的情况下计算效率很低。在这项工作中，建立了一个离散统一气体动力学格式（DUGKS）来预测参与介质中的辐射传热。通过一维瞬态辐射换热、二维稳态辐射换热和三维多尺度辐射换热三种情况，详细比较了DUGKS与传统方法的数值性能。由于该方法具有渐近保持特性，对于光学厚度的大、小和中间值，该方法给出了准确可靠的数值解，特别是在光学厚度范围内，DUGKS比传统的数值模型具有明显的计算效率优势。此外，DUGKS在参与介质内从光薄到光厚过渡的多尺度辐射传热研究中具有很好的潜力。
The radiative transfer equation (RTE) has two asymptotic regimes characterized by the optical thickness, namely, optically thin and optically thick regimes. In the optically thin regime, a ballistic or kinetic transport is dominant. In the optically thick regime, energy transport is totally dominated by multiple collisions between photons; that is, the photons propagate by means of diffusion. To obtain convergent solutions to the RTE, conventional numerical schemes have a strong dependence on the number of spatial grids, which leads to a serious computational inefficiency in the regime where the diffusion is predominant. In this work, a discrete unified gas kinetic scheme (DUGKS) is developed to predict radiative heat transfer in participating media. Numerical performances of the DUGKS are compared in detail with conventional methods through three cases including one-dimensional transient radiative heat transfer, two-dimensional steady radiative heat transfer, and three-dimensional multiscale radiative heat transfer. Due to the asymptotic preserving property, the present method with relatively coarse grids gives accurate and reliable numerical solutions for large, small, and in-between values of optical thickness, and, especially in the optically thick regime, the DUGKS demonstrates a pronounced computational efficiency advantage over the conventional numerical models. In addition, the DUGKS has a promising potential in the study of multiscale radiative heat transfer inside the participating medium with a transition from optically thin to optically thick regimes.