A fractal structure featuring symmetric/asymmetric airfoil fins is embedded within the smooth channels of the printed circuit heat exchanger (PCHE), significantly enhancing its heat transfer performance. In this study, a horizontally installed two-layer channel configuration is examined, with hot CO flowing through the upper channel and cold CO through the lower channel. Two distinct airfoil fin designs, namely NACA 0021 symmetric and NACA 4822 asymmetric, are tested for their channel reinforcement effect. The numerical analysis reveals that channels equipped with these fins exhibit substantially improved heat transfer compared to smooth channels. Notably, the comprehensive evaluation index for the asymmetric airfoil fin channel is enhanced by a factor ranging from 1.05 to 3.76. Moreover, despite a modest increase in pressure drop, indicated by a dimensionless friction factor of 0.67–1.31, the heat transfer performance remains superior. Crucially, optimal heat transfer does not rely solely on high fluid flow rates but instead demands an apt flow matching between the hot and cold fluid channels.

中文翻译：

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分形翼型翅片PCHE中超临界二氧化碳传热性能及强化机理研究


印刷电路热交换器（PCHE）的光滑通道中嵌入了具有对称/不对称翼型翅片的分形结构，显着增强了其传热性能。在这项研究中，研究了水平安装的两层通道配置，热二氧化碳流过上层通道，冷二氧化碳流过下层通道。对两种不同的翼型翅片设计（即 NACA 0021 对称型和 NACA 4822 非对称型）的通道强化效果进行了测试。数值分析表明，与光滑通道相比，配备这些翅片的通道表现出显着改善的传热性能。值得注意的是，非对称翼型翅片通道的综合评价指数提高了1.05至3.76倍。此外，尽管压降略有增加（无量纲摩擦系数为 0.67-1.31），但传热性能仍然优越。至关重要的是，最佳传热不仅仅依赖于高流体流速，还需要热流体通道和冷流体通道之间的适当流量匹配。