The effect of geometrical parameters on thermohydraulic characteristics of plain fin-and-flat tube heat exchangers: A CFD and Taguchi approach

Abstract

The present work evaluated the effect of the geometrical parameters of plain fin-and-flat tube heat exchangers on the thermohydraulic characteristics of the air side in a laminar flow regime. The influence of a 21.4–25.4 mm transverse tube pitch, a 17–21 mm longitudinal tube pitch, and three flat-tube configurations with a constant cross-sectional perimeter were considered. The Taguchi method and a numerical simulation were applied in the analysis. The results indicated that the large longitudinal tube pitch and the flat tubes with a small aspect ratio yielded benefits in terms of the area goodness factor (AGF) and the thermohydraulic performance index (JF). The tube configuration had the highest influence on the JF and AGF, with a contribution percentage of 77.89–94.38 % and 70.36–81.33 %, respectively. The optimization analysis determined the configurations that yielded the highest AGF or JF. The optimal configurations resulted in an AGF increase of 40.8–67.5 % and a JF increase of 14.1–21.8 % compared with the configurations using circular tubes. The results can be referenced in the design of air-cooled heat exchangers using flat tubes in practical applications.