NanoFluids—A New Promising Fluid for Cooling

Abstract

The ability of conventional fluids to conduct heat is significantly inferior to solids. The motivation to increase fluid thermal characteristics is not a novel idea. Initial experiments involved adding solid particles with more desirable properties to the base fluid under the hypothesis that the overall mixture's thermal behaviour would be more favourable. The recent advance in materials technology has made it possible by producing nanofluids. These are produced by suspending metallic or nonmetallic nanometer-sized solid particles in base fluids. These suspended nanoparticles can change the transport and thermal properties of the base fluid. The aim of this review is to summarize recent developments in research on the stability, enhancement of thermal conductivities, viscosity and heat transfer characteristics of nanofluids. As is evident in this report, extensive research has been carried out in Alumina-water and CuO-water systems besides few reports in Cu-water, and carbon nanotube (CNT) based systems. The nanoparticles used in three main systems, such as Al2O3-based, CuO-based and Cu-based nanofluids were varied in the range of 13–300, 23–29 and 50–300 nm respectively. The improvement in the thermal conductivity in such systems was varied in the range of 1.10–1.29, 1.07–1.54 and 1.002–1.24 respectively. Limited reports are available in zirconia, SiC, SiO2, CeO2, Fe and TiO2-based nanofluids in oil and ethylene glycol-based fluids. The review also highlights some important applications of such materials which are expanding. The article mainly focuses on the experimental results and hence the theoretical models have not been considered for analysis.