Abstract We studied the thermal and flow performance of tube heat exchangers with novel fin designs for tube tilt angles of 0°, 20°, 30° and 40° to the horizontal. The novel fin designs target to enhance the conduction heat transfer within the fin and the convective heat transfer along the fin surface simultaneously. Tubes with three different fin designs, the circular plain fin (CPF), the circular integrated pin fin (CIPF) and the serrated integrated pin fin (SIPF), were additively manufactured by selective laser melting and experimentally investigated in an air flow channel for Reynolds number between 1800 and 7800. We analysed the performance evaluation criterion, the volumetric heat flux density and the global performance criterion. It was found, that the SIPF achieves highest performance evaluation criterion and the CPF performs worst. Thus, the SIPF is recommended, when the required surface area, the material cost and the weight of the finned tube heat exchanger are relevant. Highest heat transfer per volume heat exchanger and temperature difference was achieved for the CIPF at highest tube tilt angle. The value of the global performance criterion strongly depends on the fin design and the tube tilt angle. For the horizontal orientation the CPF reaches highest global performance and for the 40∘ tube tilt angle the CIPF gives best performance. From the experimental data we derived appropriate heat transfer correlations for Reynolds number, Prandtl number, tube tilt angle and fin designs.

中文翻译：

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具有新颖翅片设计的倾斜椭圆管的热和流动性能

摘要 我们研究了具有新型翅片设计的管式换热器的热和流动性能，管子与水平面的倾斜角为 0°、20°、30° 和 40°。新颖的翅片设计旨在同时增强翅片内的传导热传递和沿翅片表面的对流热传递。具有三种不同翅片设计的管，圆形平面翅片 (CPF)、圆形集成针翅 (CIPF) 和锯齿集成针翅 (SIPF)，通过选择性激光熔化增材制造，并在雷诺的气流通道中进行了实验研究数量在 1800 到 7800 之间。我们分析了性能评估标准、体积热通量密度和全局性能标准。结果表明，SIPF达到了最高的性能评价标准，而CPF的表现最差。因此，当所需的表面积、材料成本和翅片管换热器的重量相关时，建议使用 SIPF。在最高的管倾斜角下，CIPF 实现了单位体积换热器的最高传热和温差。整体性能标准的值在很大程度上取决于翅片设计和管倾斜角。对于水平方向，CPF 达到最高的整体性能，对于 40 ∘ 管倾斜角，CIPF 提供最佳性能。从实验数据中，我们得出了雷诺数、普朗特数、管倾斜角和翅片设计的适当传热相关性。在最高的管倾斜角下，CIPF 实现了单位体积换热器的最高传热和温差。整体性能标准的值在很大程度上取决于翅片设计和管倾斜角。对于水平方向，CPF 达到最高的整体性能，对于 40 ∘ 管倾斜角，CIPF 提供最佳性能。从实验数据中，我们得出了雷诺数、普朗特数、管倾斜角和翅片设计的适当传热相关性。在最高的管倾斜角下，CIPF 实现了单位体积换热器的最高传热和温差。整体性能标准的值在很大程度上取决于翅片设计和管倾斜角。对于水平方向，CPF 达到最高的整体性能，对于 40 ∘ 管倾斜角，CIPF 提供最佳性能。从实验数据中，我们得出了雷诺数、普朗特数、管倾斜角和翅片设计的适当传热相关性。