The present study proposed some novel designs that can surpass the most widely used louver fin geometry for air-cooling applications. Innovative fin types such as ring fins, circular disk fins, and hexagonal disk fins are numerically modeled and compared with a louver fin-and-flat tube heat exchanger in terms of thermal resistance in the same pumping power. Flow visualization is also carried out by particle image velocimetry (PIV) method for hexagonal disk fins for qualitative validation. Results show that although ring fins can force the airflow toward the flat tubes, they are not able to effectively reduce thermal resistance. Meanwhile, using four circular disk fins can yield a lower thermal resistance by up to 16%. The delta winglets can be added onto the circular disk fins for further augmentation. The hexagonal disk fins can also offer similar improvement like circular disk fins but include some unique features for easier fabrication and assembly with the maximum penalty of 4% increase in thermal resistance relative to the circular disk fins. The flow visualization by PIV method is performed for inline hexagonal disk fins, which qualitatively confirms the numerical simulations regarding the proposed novel fin patterns.

中文翻译：

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创新的翅片设计，可提高翅片管和平板管式热交换器的空气侧性能

本研究提出了一些新颖的设计，这些设计可以超越用于空气冷却应用的最广泛使用的百叶窗鳍几何形状。对新型翅片类型（如环形翅片，圆盘翅片和六角形盘翅片）进行了数值建模，并在相同的泵送功率下，将其与百叶窗式扁平管式热交换器的热阻进行了比较。流动可视化还通过粒子图像测速（PIV）方法进行，用于六角形圆盘翅片，以进行定性验证。结果表明，尽管环形散热片可以迫使气流流向扁平管，但它们不能有效地降低热阻。同时，使用四个圆盘翅片可产生高达16％的较低的热阻。可以将三角翼小翼添加到圆盘鳍片上，以进一步扩大。六角形圆盘翅片还可以提供与圆盘翅片类似的改进，但包括一些独特的特征，可简化制造和组装，相对于圆盘翅片，最大热阻增加4％。通过PIV方法对直列六角形圆盘翅片进行流动可视化，从质量上证实了有关所提出的新型翅片图案的数值模拟。