Mathivanan, E. and Liu, L., "Impact of Nanofluids on Heat Transfer Performance of a Motorcycle Radiator," SAE Technical Paper 2016-01-0188, 2016, doi:10.4271/2016-01-0188.
In the present work, the effect of various nanofluids on convective heat transfer performance in an automotive radiator was analyzed based on measured nanofluid properties. Al2O3, TiC, SiC, MWNT (multi-walled nanotube) and SiO2 nanoparticles ranging between 1 and 100 nm in size were dispersed in distilled water to form nanofluids. An ultrasonic generator was used to provide uniform particle dispersion in the fluid and keep the mixture stable for a long period of time. The impact of various particle types and their volume concentration on fluid properties such as density, thermal conductivity and viscosity were experimentally analyzed. It is observed that the nanofluid properties increased with the increase in particle volume concentration. TiO2 nanofluids were observed to show the highest increase in density (2.6% higher than the base fluid at a 1% vol. concentration) and also the largest enhancement in thermal conductivity (7.5% augmentation at 1% concentration). SiO2 nanofluids exhibited to be the most viscous, with a 47% increase in viscosity over base fluid at a 1% vol. concentration. Empirical correlations were then used to predict the convective heat transfer coefficient for laminar nanofluid flows. The effect of nanoparticle volume concentrations on Nusselt number and heat transfer coefficient were investigated. The results showed that SiO2 nanofluids had the highest enhancement in the heat transfer coefficient. At a Reynolds number of 1000, the enhancement of heat transfer coefficient over the base fluid for a 1% volume concentration of SiO2, Al2O3 and TiO2 nanofluids are 35.3%, 35.1% and 30.5% respectively.