Mohammadreza Behi
The University of Sydney, Australia
Title: Effect of particle size on the rheology of the Nano-engineered fluids (Al2O3 Nanofluid)
Biography
Biography: Mohammadreza Behi
Abstract
Over the last decade, there has been a great deal of interest and development in nanofluidic coolants. Thermophysical properties of nanofluids (NFs) have been broadly studied; however, their rheological behavior that plays a pivotal role for their application compels a thorough investigation. Therefore, the objective of the present study was to evaluate the effect of nanoparticles size on the shearing viscosity and stress behaviour of alumina NFs. The Al2O3 NFs were prepared by dispersing three different nanoparticle sizes in the basefluid (40 nm, 150 nm, and 250 nm). A mixture of distilled water and ethylene glycol (DW-EG) 50:50 weight ratio was used as a basefluid. Effect of different nanoparticle size on rheological properties of NF was measured in a constant volume concentration (2.57 Vol%). A rotational method was used to investigate the rheological behaviour of these NFs at ambient temperature. Our results demonstrated that the dispersion of the nanoparticle with different sizes did not affect the Newtonian behaviour of the basefluid. On the other hands, the shear viscosity of DW-EG was significantly increased by the addition of the nanoparticles. It was concluded that in alumina NFs system the particle size had a significant impact on shearing viscosity. The higher viscosity of NFs with smaller particles was due to their larger aspect ratios, which form stronger interplay between the cohesive-adhesive interactions in the suspension, nanoparticle–fluid, nanoparticle-nanoparticle and liquid-liquid molecules interactions. Fundamentally, it is crucial to understand the physics behind the rheological behaviour of nano-engineered coolants as it can directly affect both stability and thermal transport properties of such medium. Furthermore, several hydrothermal applications such as electronic cooling could be improved significantly by employing NFs. To achieve this goal, it is essential to conduct a comprehensive study to understand the mechanisms that elaborate the effect of particle characteristics in NFs suspensions on viscosity.