Role of hybrid-nanofluid in heat transfer enhancement – A review

Abstract

The promising thermophysical properties of mono nanofluids show great potential in various heat transfer applications. The properties of mono nanofluids can be tailored by varying the proportion/concentration of the nanoparticles. However, the mono nanofluids, employing only single-type nanoparticles (metallic or non-metallic), revealed the stable thermophysical properties in the limited range. To tailor this shortcoming, in recent years, hybrid nanofluids have been synthesized to improve the base fluid’s thermophysical properties and heat transfer characteristics. In this paper, a state-of-the-art review on the use of hybrid nanofluid in various heat transfer applications is presented. The first part of the article summarizes the existing research works on the preparation and synthesis of various hybrid nanocomposites and hybrid nanofluids. Subsequently, density, specific heat, viscosity, and thermal conductivity values of different hybrid nanofluids are tabulated, serving as a database. The collection of thermophysical properties correlations is also presented. The later part of the article covers the hydrothermal behavior of hybrid nanofluids in various heat transfer applications such as heat exchangers, heat sinks, heat pipes, solar panels, natural convection enclosures/cavities, air conditioning systems, impingement jet cooling, thermal energy storage, and boiling-related applications. In addition, the Nusselt number and friction factor correlations are tabulated for different heat transfer applications. Finally, the challenges associated with hybrid nanofluids and future research scopes are presented.