Experimental study of moist air condensation outside three-dimensional finned tubes with different fin parameters

Abstract

The condensation of moist air is a common phenomenon in daily life and industry, and increasing its heat transfer coefficient has always been a hot spot in research. Three-dimensional (3-D) finned tube is an effective heat transfer enhancement element and its fin parameters have an important influence on the enhancement result. This study carried out experiments using orthogonal design and Taguchi method to determine the influence of 3-D fin parameters on moist air condensation. The contribution ratios of axial fin spacing, fin height, fin width, and circumferential fin spacing on the heat transfer coefficient were obtained and analyzed in detail. Meanwhile, the photos of condensation processes were obtained. Experimental results show that all the heat transfer coefficient increased with the increase of relative humidity (RH) or the decrease of cooling water inlet temperature. Besides, all the 3-D finned tubes had higher heat transfer coefficient compared with smooth tube. The contribution ratio of fin height on the heat transfer coefficient was the highest, which can be 75.7% at most. Besides, the contribution ratio of axial fin spacing increased from 10.1% to 24.0% with the increase of RH. The optimal parameters combination of 3-D fins within the range of this experiment was also recommended. The results obtained in this study can provide guidance for the design and optimization of 3-D finned tubes used in moist air condensation.