This paper presents nonlinear iterative methods for the fundamental thermal radiative transfer (TRT) model defined by the time-dependent multifrequency radiative transfer (RT) equation and the material energy balance (MEB) equation. The iterative methods are based on the nonlinear projection approach and use multiple grids in photon frequency. They are formulated by the high-order RT equation on a given grid in photon frequency and low-order moment equations on a hierarchy of frequency grids. The material temperature is evaluated in the subspace of the lowest dimensionality from the MEB equation coupled to the effective grey low-order equations. The algorithms apply various multigrid cycles to visit frequency grids. Numerical results are presented to demonstrate convergence of the multigrid iterative algorithms in TRT problems with large number of photon frequency groups.

中文翻译：

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用于热辐射传输的光子频率多重网格非线性迭代投影方法

本文介绍了由瞬态多频辐射传递 (RT) 方程和材料能量平衡 (MEB) 方程定义的基本热辐射传递 (TRT) 模型的非线性迭代方法。迭代方法基于非线性投影方法并在光子频率中使用多个网格。它们由给定光子频率网格上的高阶 RT 方程和频率网格层次结构上的低阶矩方程公式化。在耦合到有效灰度低阶方程的 MEB 方程的最低维子空间中评估材料温度。该算法应用各种多重网格周期来访问频率网格。