Heat conduction mechanism in nanofluids

Nanofluids are produced by dispersing nanoparticles in basefluid. Given its superior thermo-physical properties, nanofluids are gaining increasing attention and are showing promising potential in various applications. Numerous studies have been conducted in the past decade to experimentally and theoretically investigate thermal conductivity. The experimental finding is briefly summarized in this study; however, we do not intend to present a systematic summary of the available references from the literature. The primary objective of this study is to review and summarize the most debated mechanisms for heat conduction in nanofluids, such as the effects of a nanolayer, the Brownian motion of nanoparticles and aggregation, as well as induced convection. Finally, at a low concentration of nanoparticles, nanoconvection is the leading contributor to thermal conductivity enhancement, whereas at a higher concentration, the natural thermal transport along the backbone would aggregate, and the effects of the nanolayer would become significant and become ineligible.