09. Heat and Mass Transfer

Nanofluids are regarded as a promising fluid for improving heat transfer efficiency in various engineering applications, such as energy-harvesting thermal devices and the electronic cooling required in the era of artificial intelligence. Over the decades, a large number of studies using experimental or theoretical methods have been conducted to examine the usability of technologies. However, there have been unresolved conflicts between them, which seriously hinders the applications. In order to better understand the mechanisms behind complex convective transport phenomena, it is imperative to develop appropriate theoretical models. This study aims to use numerical methods to test the predictability of the theoretical model proposed by Chang and Ruo (J. Fluid Mech., vol. 950, 2022, A37), focusing on the effect of gravity settling of nanoparticles on the convective transport phenomena in nanofluids. The results show that the stronger the gravity settling effect, the greater the deterioration of heat transfer efficiency. This implies that the geometry and size of nanoparticles play an important role in the feasibility of nanofluid applications.