The problem of heat removal in energetic processes represents a big challenge especially because of the enhanced requirements of the modern industry. The thermal exchange systems therefore have to guarantee better performances in correspondence to ever more severe dimensional constraints. This paper shows a numerical approach, based on computational fluid dynamics (CFD) software, for the evaluation of the heat exchange performances of finned (straight fins) surfaces made of highly heat conductive material. The same geometric constraints assumed in a reference work were adopted. This research attempts to develop an easy-to-use method to face what was previously solved by the powerful approach of Bejan’s Constructal theory. The results obtained show a good agreement between CFD and the Constructal theory’s results, validating, therefore, the simplified approach proposed and encouraging its application to a broader variety of geometries.