The present work investigates the thermal radiation transport inside porous media under local thermal non-equilibrium conditions. Two different geometrical situations, a two-dimensional channel and a cylindrical geometry, are considered in the analysis. Porous media application is generally associated with high-temperature combustion, and radiative heat transfer is dominant. In this paper, by considering a stream of high-temperature flow in geometries filled with porous medium, the effect of thermal radiation on the solid- and fluid-phase temperature fields is calculated and analyzed. Two radiative heat transfer techniques, the discrete ordinate method (DOM) and the finite volume method (FVM), are tested, and the results are compared with a non-radiative model and with a model-based Rosseland approximation. A sensitivity study for the variation in absorption and scattering coefficients and the effect on the solid- and fluid-phase temperature fields is also undertaken. The effect of the extinction coefficient on the Nusselt number is also examined. The temperatures obtained through the Rosseland model show differences up to + 34% and − 26% compared to temperatures calculated with the DOM or FVM radiation calculation methods. The temperature fields obtained through DOM and FVM are very similar, and some significant differences can only be seen in the cases where a very low number of angular directions are used.

中文翻译：

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局部热非平衡条件下多孔介质中的热辐射分析

目前的工作研究了在局部热非平衡条件下多孔介质内的热辐射传输。分析中考虑了两种不同的几何情况，二维通道和圆柱几何。多孔介质应用通常与高温燃烧有关，辐射传热占主导地位。在本文中，通过考虑充满多孔介质的几何体中的高温流动流，计算和分析了热辐射对固相和液相温度场的影响。测试了两种辐射传热技术，即离散纵坐标法 (DOM) 和有限体积法 (FVM)，并将结果与​​非辐射模型和基于模型的 Rosseland 近似进行比较。还对吸收和散射系数的变化以及对固相和液相温度场的影响进行了敏感性研究。还检查了消光系数对努塞尔数的影响。与使用 DOM 或 FVM 辐射计算方法计算的温度相比，通过 Rosseland 模型获得的温度显示出高达 + 34% 和 - 26% 的差异。通过 DOM 和 FVM 获得的温度场非常相似，只有在使用非常少的角度方向的情况下才能看到一些显着的差异。与使用 DOM 或 FVM 辐射计算方法计算的温度相比，通过 Rosseland 模型获得的温度显示出高达 + 34% 和 - 26% 的差异。通过 DOM 和 FVM 获得的温度场非常相似，只有在使用非常少的角度方向的情况下才能看到一些显着的差异。与使用 DOM 或 FVM 辐射计算方法计算的温度相比，通过 Rosseland 模型获得的温度显示出高达 + 34% 和 - 26% 的差异。通过 DOM 和 FVM 获得的温度场非常相似，只有在使用非常少的角度方向的情况下才能看到一些显着的差异。