A Review of Nanofluids Synthesis, Factors Influencing Their Thermophysical Properties and Applications

Abstract

Heat-generating equipment (such as transformers, computer microchips, car engines, nuclear reactors, etc.) requires an efficient cooling mechanism to safeguard them from thermal degradation and to enhance their life span. The use of Nanofluids as opposed to conventional heat transfer fluids in their cooling system is to ensure that they are properly cooled. Nanofluids display superior thermal properties and they are synthesized from nanosized materials such as metals ((Copper (Cu), Silver (Ag), Nickel (Ni), and Gold (Au)), metal oxides (( Aluminum oxide (Al2O3), Cupric oxide (CuO), Magnesium oxide (MgO), Zinc oxide (ZnO), Silica (SiO2), Iron (III) oxide (Fe2O3), and Titania  (TiO2)), metal carbide (such as Silicon carbide (SiC)), metal nitride  (such as Aluminium nitride (AIN)), or Carbon materials ((Carbon nanotubes (CNTs), Multi-wall carbon nanotubes (MWCNTs), diamond, and graphite)) suspended in base fluids (such as water, ethylene glycol, engine oil, transformer oil, vegetable oil, kerosene, toluene, etc.). The current review explores methods used in the synthesis of nanofluids (One-step method, Two-step method, Solvothermal/Hydrothermal process), factors influencing their thermophysical properties (Particle volume concentration, pH, particle size, particle shape, particle material, base fluid material, temperature, shear rate, and surfactants) and their applications (Heat transfer applications, automotive applications, biomedical applications, electronic applications, Nano-based microbial fuel cells, and Nano-based brake fluids).