Review of stability enhanced nanofluids prepared by one-step methods—heat transfer mechanism and thermo-physical properties

Abstract

Nanofluids (NFs) are technologically important heat transfer fluids that are prepared by suspending nanoparticles (NPs) of size less than 100 nm in the base fluids. NFs have been employed in heat transfer applications such as solar heat exchangers, radiators, heat sinks, refrigeration systems, heat pipes, solar collectors and thermal energy storage, owing to their remarkable thermo-physical properties over conventional heat transfer fluids. However, the efficiency of the NFs primarily depends on the suspension stability. The development of NFs with excellent stability is important to bridge the gap between research and commercialization. This article is a review of one-step methods developed for the preparation of NFs with enhanced stability as compared with NFs prepared by the two-step method. This review also discusses the various analytical tools which are used to conclude the structure-property relation, particle size, thermal conductivity, stability and viscosity of the NFs. This article also highlights the determination of the thermal conductivity of HNFs by various thermal conductivity models.