Numerical Investigation of Hydrophilic and Thermal Performance of Annular Elliptical Fin Tubes in Comparison with Annular Circulars

In this study, heat transfer and pressure drop through the four-row fin tube bundle with annular elliptical fins in a triangular layout were investigated. Five different geometries in three fin densities for four different Reynolds numbers were simulated. For circular fins, results are in good agreement with empirical equations in predicting pressure drop and heat transfer. In this regard, the elliptical fins were also examined. It was found that the Nusselt numbers in horizontal elliptical fins are the least and in vertical are the highest. It was also found that pressure drop in the circular fins is higher than in horizontal or vertical elliptical fins and the vertical elliptical fins in comparison with circular fins with the same vertical diameter, exert less pressure drop. Furthermore, although the heat transfer coefficient in horizontal elliptical fins is slightly less than in circular fins, the pressure drop can be as much as 70%. The performance evaluation criterion shows that the circular fin performance is much lower compared with the elliptical fin. Finally, equations are proposed to predict the pressure drop and heat transfer coefficient for elliptical fins relative to circular fins