A hybrid numerical-experimental analysis of heat transfer by forced convection in plate-finned heat exchangers

Abstract

A hybrid numerical-experimental approach to obtain the thermal performance of heat exchangers is presented. The proposed methodology combines numerical simulation with wind tunnel experimental data to predict the average convective heat transfer coefficient and overall finned surface efficiency. The technique is applied to a plate-finned tube heat exchanger with in-line arrangement. Validation of the present methodology is performed by comparing the results against empirical correlations for the Nusselt number available in the literature. A parametric study is performed aiming to evaluate the influences of the airflow velocity (Reynolds number) and fin materials (aluminium, carbon steel and copper) upon the heat transfer characteristics. The main results indicate an increase of the average convective heat transfer coefficient with air velocity; whereas the overall fin surface efficiency presents an opposite behaviour. Furthermore, the Nusselt number based on the overall heat transfer coefficient is larger for higher conductive fin materials. In addition, aluminium and steel fins are found to be the most weight and cost-effective fin materials, respectively.