In this paper, a wall-adapted anisotropic heat flux model for large eddy simulations of complex engineering applications is proposed. First, the accuracy and physical consistency of the novel heat flux model are testified for turbulent heated channel flows with different fluid properties by comparing with conventional isotropic models. Then, the performance of the model is evaluated in case of more complex heat and fluid flow situations that are in particular relevant for internal combustion engines and engine exhaust systems. For this purpose large eddy simulations of a strongly heated pipe flow, a turbulent inclined jet impinging on a heated solid surface and a backward-facing step flow with heated walls were carried out. It turned out that the proposed heat flux model has the following advantages over existing model formulations: (1) it accounts for variable fluid properties and anisotropic effects in the unresolved temperature scales, (2) no ad-hoc treatments or dynamic procedure are required to obtain the correct near-wall behavior, (3) the formulation is consistent with the second law of thermodynamics, and (4) the model has a similar prediction accuracy and computational effort than conventional isotropic models. In particular, it is shown that the proposed heat flux model is the only model under consideration that is able to predict the direction of subgrid-scale heat fluxes correctly, also under realistic heat and fluid flow conditions in complex engineering applications.

中文翻译：

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用于复杂湍流热流大涡模拟的壁面自适应各向异性热流模型

在本文中，提出了一种用于复杂工程应用的大涡模拟的壁面适应各向异性热通量模型。首先，通过与传统的各向同性模型进行比较，验证了具有不同流体特性的湍流加热通道流动的新型热通量模型的准确性和物理一致性。然后，在更复杂的热和流体流动情况下评估模型的性能，这些情况尤其与内燃机和发动机排气系统相关。为此，对强烈加热的管流、撞击加热固体表面的湍流倾斜射流和具有加热壁的反向阶梯流进行了大涡模拟。结果表明，所提出的热通量模型与现有模型公式相比具有以下优势：(1) 它在未解析的温度范围内考虑了可变的流体性质和各向异性效应，(2) 不需要特殊处理或动态程序来获得正确的近壁行为，(3) 公式与第二个一致热力学定律，以及 (4) 该模型具有与传统各向同性模型相似的预测精度和计算量。特别是，表明所提出的热通量模型是唯一能够正确预测亚网格尺度热通量方向的模型，在复杂工程应用中的真实热和流体流动条件下也是如此。(3) 公式符合热力学第二定律，以及 (4) 该模型具有与传统各向同性模型相似的预测精度和计算量。特别是，表明所提出的热通量模型是唯一能够正确预测亚网格尺度热通量方向的模型，在复杂工程应用中的真实热和流体流动条件下也是如此。(3) 公式符合热力学第二定律，以及 (4) 该模型具有与传统各向同性模型相似的预测精度和计算量。特别是，表明所提出的热通量模型是唯一能够正确预测亚网格尺度热通量方向的模型，在复杂工程应用中的真实热和流体流动条件下也是如此。