Research Information System
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS, PART C: JOURNAL OF MECHANICAL ENGINEERING SCIENCE, no.1, pp.1-18, 2025 (SCI-Expanded)
Annular fins, commonly used in various engineering applications from heat exchangers to electrical equipment, are
typically made from highly conductive homogeneous materials. However, these materials, such as aluminum, do not
achieve ideal uniform temperature distribution along the fins’ length. Recognizing the potential of Functionally Graded
Materials (FGMs) to enhance thermal performance by combining two distinct materials with a gradual transition, this
study proposes their use as fin materials to achieve optimal performance. The study encompasses three primary
components: (1) finite element analysis to determine the optimal FG annular fin design, (2) fabrication of aluminum and
FG fins using powder metallurgy and hot pressing techniques, and (3) experiments to evaluate the thermal
performance of FG and aluminum fin arrays by attaching them to a cylinder under natural convection. This study
distinguishes itself by elucidating the effects of tilt angle, fin number, and material on natural convection heat transfer. It
is also the first experimental study to assess the performance of FG fins on a cylinder with inclinations ranging from 0
to 75 degrees. In these experiments, the thermal performance of fin arrays is evaluated for heat inputs ranging from 25
to 50W, different fin numbers, and cylinder inclinations. The results clearly indicate that the thermal performance of fin
arrays depends on tilt angle, fin material, and spacing. FG fin arrays outperform aluminum fin arrays for all
configurations, demonstrating an 18% improvement in heat transfer, and the optimal performance is achieved with fin
arrays containing seven fins. Additionally, increasing tilt angle deteriorates natural convective heat transfer, regardless of
fin material.