Effects of temperature and nanoparticles concentration on rheological behavior of Fe3O4-Ag/EG hybrid nanofluid: An experimental study

In this paper, the effects of temperature and nanoparticles concentration on the rheological behavior of Fe3O4-Ag/EG hybrid nanofluid have been experimentally investigated. Stable and homogeneous suspensions were prepared in solid volume fractions of 0.0375%, 0.075%, 0.15%, 0.3%, 0.6% and 1.2%. Viscosity measurements were performed at different shear rates (12.23-122.3 s(-1)) under temperatures ranging from 25 degrees C to 50 degrees C. Results revealed that the nanofluid samples with solid volume fractions of less than 0.3% had Newtonian behavior, while those with higher solid volume fractions (0.6% and 1.2%) had non Newtonian behavior, and followed the power-law model. Finally, the consistency index and power-law index were obtained from curve-fitting on shear stress-shear rate dependency. Curve-fitting results showed that all power-law indices were in the range of 0.5339-0.6706, indicating that the nanofluid samples possessed shear-thinning behavior at all temperatures considered. (C) 2016 Elsevier Inc. All rights reserved.