Efficiency and Effectiveness of a Fin Having Capsule-Shaped Cross Section Dependent on the One-Dimensional Position

In this paper, we investigate the efficiency and effectiveness of a special form of fin to accelerate heat transfer in a system when the state is unsteady. The fin has capsule-shaped form in its cross sections. The area of the cross section is dependent on its one-dimensional position. The closer the position to the heat source, we have that the area of the fin cross section is larger. The further the position from the heat source, we have that the area of the fin cross section is smaller. The aim of the research is to investigate the influence of the convection heat transfer coefficient, fin material, and fin slope to the efficiency and effectiveness of fin in the unsteady state condition. In the heat transfer within the fin, we assume that the conduction heat transfer coefficient is dependent on the temperature. The solving method is an explicit finite difference method. We obtain three findings for unsteady state conditions. First, the larger the convection heat transfer coefficient, we have that the smaller the efficiency and the effectiveness of the fin. Second, in the unsteady state condition, the materials influence the efficiency and effectiveness of the fin in an unstructured way. Third, when we observe the influence of fin slope of angles 1.5o, 1.75o, 2o, 2.25o, and 2.5o, we obtain that the fin slope of angle 2.5o leads to the worst efficiency, and the effectiveness gets smaller with respect to time.