发表机构
North Carolina State University（北卡罗来纳州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过孔隙分辨模拟研究方形钝体尾流撞击多孔层的传热增强，发现界面局部传热增强最高达18.2%，但高雷诺数下因尾流动量亏损导致传热反而降低。
AI 中文摘要
外部产生的尾流可在若干实际传热应用中撞击多孔层。然而，这些宏观尺度涡旋的输运及其对多孔层内传热的影响仍然未知。本文采用二维孔隙分辨模拟，研究了方形钝体尾流撞击由在线排列的加热方形障碍物组成的多孔层，参数范围为Re = 500-4000，Pr = 0.7和7.0，孔隙率φ = 0.75、0.85和0.95。入射的宏观尺度涡旋从多孔-流体界面处立即开始分解。在该入口区域经历宏观尺度湍流热输运后，下游的波动与孔隙几何结构对齐，并在微观尺度上由孔隙喉部剪切、分离和重复的障碍物尾流产生。直接撞击通过相对于非撞击区域提高局部努塞尔数，局部改善了多孔-流体界面处的传热。界面传热增强随孔隙率、雷诺数和普朗特数变化，在φ = 0.85、Pr = 7.0和Re = 1000时观察到峰值增强18.2%。与尾流相关的宏观尺度湍流热通量贡献在一致的入口区域内衰减，该区域在所有研究的孔隙率、雷诺数和普朗特数下延伸约3-4个单元进入多孔层。对于Re≥1000，持续的尾流动量亏损随后导致传热对比变为负值，导致撞击区域的传热低于非撞击区域。
英文摘要
Externally generated wakes can impinge on porous layers in several practical heat transfer applications. However, the transport of these macroscale vortices and their resulting influence on heat transfer in the porous layer remain unknown. In this paper, two-dimensional pore-resolved simulations are used to examine a square-bluff-body wake impinging on a porous layer composed of an in-line array of heated square obstacles at Re = 500-4000, Pr = 0.7 and 7.0, and porosities $ϕ$ = 0.75, 0.85, and 0.95. The incident macroscale vortices break down starting immediately at the porous-fluid interface. Following macroscale turbulent thermal transport in this entrance region, fluctuations farther downstream are aligned with the pore geometry and are generated at the microscale level by pore-throat shear, separation, and repeated obstacle wakes. Direct impact locally improves heat transfer at the porous-fluid interface by increasing the local Nusselt number relative to a non-impingement region. The interfacial heat-transfer enhancement varies with porosity, Reynolds number, and Prandtl number, with a peak enhancement of 18.2% observed for $ϕ$ = 0.85, Pr = 7.0, and Re = 1000. The wake-associated macroscale turbulent heat-flux contribution decays within a consistence entrance region extending approximately 3-4 unit cells into the porous layer across all investigated porosities, Reynolds numbers, and Prandtl numbers. For Re$\ge$1000, the persistent wake momentum deficit subsequently causes the heat-transfer contrast to become negative, resulting in lower heat transfer in the impingement region than in the non-impingement region.
