Experimental Research and Development on the Natural Convection of Suspensions of Nanoparticles—A Comprehensive Review

Abstract

Suspensions of nanoparticles, widely known as nanofluids, are considered as advanced heat transfer media for thermal management and conversion systems. Research on their convective thermal transport is of paramount importance for their applications in such systems such as heat exchangers and solar collectors. This paper presents experimental research on the natural convection heat transfer performances of nanofluids in different geometries from thermal management and conversion perspectives. Experimental results and available experiment-derived correlations for the natural thermal convection of nanofluids are critically analyzed. Other features such as nanofluid preparation, stability evaluation and thermophysical properties of nanofluids that are important for this thermal transfer feature are also briefly reviewed and discussed. Additionally, techniques (active and passive) employed for enhancing the thermo-convection of nanofluids in different geometries are highlighted and discussed. Hybrid nanofluids are featured in this work as the newest class of nanofluids, with particular focuses on the thermophysical properties and natural convection heat transfer performance in enclosures. It is demonstrated that there has been a lack of accurate stability evaluation given the inconsistencies of available results on these properties and features of nanofluids. Although nanofluids exhibit enhanced thermophysical properties such as viscosity and thermal conductivity, convective heat transfer coefficients were observed to deteriorate in some cases when nanofluids were used, especially for nanoparticle concentrations of more than 0.1 vol.%. However, there are inconsistencies in the literature results, and the underlying mechanisms are also not yet well-understood despite their great importance for practical applications.

Optimization of Thermophysical and Rheological Properties of Mxene Ionanofluids for Hybrid Solar Photovoltaic/Thermal Systems

“…Many researchers around the world have focused nanofluids as they provide the possibility of increased heat transfer for various purposes including cooling of thermal power plants, electronics, manufacturing and transportation. Most of the nanofluids’ works as heat transfer fluid (HTF) have concentrated on utilizing typical 2D nanoparticles such as graphene or conventional nanoparticles namely copper, silver, gold, aluminum oxide, copper oxide and silicon carbide [ 1 , 2 , 3 , 4 ]. For example, Wang et al [ 5 ] showed a thermal conductivity enhancement of 14.2% using graphene nanoparticles in ethylene glycol base fluid.…”

Thermophysical profile of ethylene glycol based nanofluids containing two types of carbon black nanoparticles with different specific surface areas

“…Since then research work in order to find out more about the properties has risen. The current stage of knowledge on the thermo-physical properties of nanofluids can be found in recent review papers [3,4,5,6,7,8,9,10,11,12,13]. Thermophysical properties and possible applications of nanofluids containing various types of carbon structures have been summarized in Refs.…”

Natural Convection in a Partially Heated Parallelogrammical Cavity With v-Shaped Baffle and Filled With Various Nanofluids

“…Changing the shape or inclination of the cavities (Hussein and Mustafa, 2014;Qi et al, 2017;Selimefendigil, 2017;Majdi et al, 2019;Loganathan et al, 2021) is the common technique. Other researchers enhancing the working fluid properties by using fluid additives such as nanoparticles, which improve the thermal conductivity and the heat transfer performance, where different nanofluids has been reported in literatures (Safiei et al, 2020;Murshed et al, 2020;Ahmadi et al, 2018;Devendiran and Amirtham, 2016;Sidika et al, 2017). As well as, adding baffles of different shapes is one of these techniques of enhancement.…”