Review of the mechanisms responsible for heat transfer enhancement using nanofluids

This work presents a review of the latest developments regarding the mechanisms that influence the enhancement of heat transfer by using nanofluids. The first part of the paper addresses studies regarding how nanoparticles affect the thermal transport mechanisms, stating that the Brownian motion of nanoparticles, particle clustering and the formation of an interface layer around the nanoparticle are widely acknowledged as being major developments in this area. This part is followed by a review of the most important studies regarding thermal conductivity enhancement and the enhancement of the heat transfer coefficients in nanofluids convection and boiling applications. This review presents many approaches in order to describe the physical behaviour of several nanofluids under different conditions. At the end, it is summarized the main difficulties and challenges that still remain a target for future studies regarding nanofluids.