Review of ternary hybrid nanofluid: Synthesis, stability, thermophysical properties, heat transfer applications, and environmental effects

Decade research on nanofluids have solidified the claim that they have excellent heat transfer properties. The properties of mono nanofluids can be optimized by varying the volume concentration of the nanoparticle, however, there is a limit to this due to the challenge of the trade-off of the net negative of viscosity increase. In resolving this limitation, hybrid nanofluids have been synthesized by researchers to maximize the unique properties of different types of nanoparticles. The early days of hybrid nanofluid experimentations consisted of two-particle nanofluids, however, in recent years, a new class of working fluids has been discovered and extensively explored, consisting of three solid nanoparticles dispersed in a conventional fluid. These fluids are referred to as 'ternary nanofluid, 'ternary hybrid nanofluid' or 'trihybrid nanofluids'. This paper gives a comprehensive review of all studies that have synthesized this new class of nanofluids. The major focus in this study was given to their synthesis methods, characterizations, stability tests, thermophysical properties (thermal conductivity, specific heat capacity, and viscosity). This study also reviews the heat transfer applications of ternary nanofluids. The ternary nanofluids are shown to significantly increase the thermal conductivity and heat transfer properties of base fluids. The type and sizes, as well as mixture ratio of nanoparticles are important factors that determine the effectiveness of ternary nanofluids. Several areas still need to be covered for proper understanding of the hybridization effects of three particle nanofluids, like the effect of combining different nanoparticle types, particle sizes, nanoparticle shape, and base fluids.