A review of the internal forced convective heat transfer characteristics of nanofluids: Experimental features,mechanisms and thermal performance criteria

In this review paper, we summarize important milestones in experimental studies that indicate the effects of volume fraction, nanoparticle size, operating temperature and pH on the internal forced convective heat transfer characteristics of nanofluids. In addition, many mechanisms for the enhancement of the convective heat transfer coefficient of nanofluids proposed by investigators are categorized into two dominant mechanisms. The first dominant mechanism is properties’ change of nanofluids such as thermal conductivity and viscosity. The other is the motion of nanoparticles in nanofluid flow due to Brownian motion, thermal dispersion and migration. Finally, the thermal performance criteria which can estimate whether nanofluids are useful in actual engineering systems, are summarized. Authors expect that the understanding of the convective heat transfer characteristics of nanofluids could help many thermal engineers to develop nanofluids which can be used in industrial applications.