Local air-side heat transfer coefficients (HTCs) of real-scale heat exchanger fins have been experimentally investigated in the current study. A recently developed absorption-based mass transfer method has been employed to visualize and obtain two-dimensional HTC distributions on different fins at a high resolution (8.6 µm). The process involves a mass transfer from airflow to a color change thin film coating. The local mass transfer is obtained through observing and quantifying the color change. Thus, local HTCs can be determined by applying the analogy between heat and mass transfer. The accuracy of this absorption-based experimental method has been validated on external flow across a flat plate which shows good agreement compared to the analytical solution. Moreover, the averaged HTCs and pressure drops of the three fin-and-tube arrays in the current study agree well with data from other researchers who have measured entire heat exchangers with similar fin geometries. To the authors’ best knowledge, this is the first time that local HTCs for real-scale heat exchanger fins with complex surface geometries have been experimentally obtained and published in the open literature. Moreover, the degradation of the HTCs with increasing row numbers of the three fin types has been quantified. The data shows the plain fin with inline tube arrangement has the largest HTC degradation in the second row compared to the wavy fin and louver fin with staggered tube arrangement. The method of the current study has provided a way to obtain a local and reliable comparison of heat transfer on different fin shapes. It can be utilized to generate better HTC correlations for heat exchangers and to recognize opportunities for improvement.

在当前研究中，已经通过实验研究了实际规模的散热片的局部空气侧传热系数（HTC）。最近采用的基于吸收的传质方法已被用来可视化并获得高分辨率（8.6 µm）的不同鳍片上的二维HTC分布。该过程涉及从气流到变色薄膜涂层的质量转移。通过观察和定量颜色变化获得局部质量传递。因此，可以通过在传热和传质之间进行类比来确定局部HTC。这种基于吸收的实验方法的准确性已通过平板上的外部流动进行了验证，与分析解决方案相比，该流动显示出良好的一致性。而且，当前研究中三个翅片和管阵列的平均HTC和压降与其他研究人员的数据非常吻合，这些研究人员测量了具有类似翅片几何形状的整个热交换器。据作者所知，这是首次通过实验获得用于具有复杂表面几何形状的实际规模的散热片的本地HTC，并将其发布在公开文献中。此外，已经量化了随着三种鳍片类型的行数增加而导致的HTC的退化。数据显示，与交错管排列的波浪状翅片和百叶窗式翅片相比，具有串联管排列的普通翅片在第二排中的HTC降解最大。当前研究的方法提供了一种获得不同鳍形传热的局部和可靠比较的方法。