Thorny Durian-inspired enhanced microscale heat transfer in macro geometry

This paper demonstrates the feasibility of achieving superior enhanced microscale heat transfer effects in macro geometry systems while employing economical and readily available conventional fabrication techniques. An annular microchannel, of mean channel gap 300 μm and length 30 mm, is formed by securing a cylindrical insert of mean diameter 19.4 mm within a cylindrical pipe of internal diameter 20 mm. Inspired by the husk of a tropical fruit, the thorny Durian (D) enhancement profile is introduced on the insert surface to improve the convective heat transfer coefficient, for a constant heat transfer area. The effect of seven D enhancement profiles on the heat transfer and flow characteristics are experimentally studied using water, with a Reynolds number range of 350-4,600. Results show that the best-performing D microchannel can reduce heat exchange surface area by about 54%, increase heat transfer by about 67%, and reduce pumping power by about 79%.