Heat transfer enhancement of the air-cooled engine fins through geometrical and material analysis: A review

Energy crisis and air pollution are the two leading scientific issues that require global attention. The fundamental reason for the rise in energy costs is the rapid depletion of fossil fuels which has raised fuel prices. Analysis of IC engines suggests that thermodynamic constraints cause more than half of energy derived from fossil fuels to be lost to the environment. Prolonged working at high temperatures can alter an engine's performance and characteristics. One way of minimizing these losses is to regulate and keep the engine's temperature within the permissible range. Thus, cylinder blocks often include extended surfaces called fins to transfer away the heat from the engine surface. This study focuses on explaining the effect of variation in material, type, design, number of fins, and other parameters in improving fins' efficiency and enhancing the engine's performance. It has been observed that the optimum number of fins can significantly improve fin efficiency, and a 5% to 13% enhancement in heat transfer is possible through fin extension. Elliptical shape fins perform better than triangular and rectangular fins. However, circular and curved fins increase engine efficiency by reducing engine weight. Amongst various fin materials like Cast Iron, Copper, Magnesium, Aluminum, and its alloys, etc., more thermal flux has been observed for Aluminium Alloy 6082. Finally, authors have come to a conclusion that circular fins with holes and slots offer a higher heat transfer rate and improved engine performance at reduced material requirements. The circular fin geometry with slots and holes provides further scope of improvement by optimizing fin thickness, number of holes and slots, their dimensions and spacing to come with a combination that provides effective cooling along with ease of manufacturing in case of lightweight engines.