Experimental investigation of the effects of temperature and nanoparticles volume fraction on the viscosity of non-Newtonian hybrid nanofluid

In this paper, the effects of temperature and nanoparticles volume fraction on the viscosity of non-Newtonian hybrid nanofluid, containing water and ethylene glycol as a base fluid and multi-walled carbon nanotubes (MWCNTs) and silica (SiO2) as additives, have been investigated experimentally. The measurements have been carried out in temperatures range of 27.5°C - 50°C by using a Brookfield DV-I PRIME digital Viscometer for different shear rates. The stable and homogeneous samples, with the solid volume fractions of 0.0625%, 0.25%, 0.5%, 0.75%, 1%, 1.5% and 2%, were prepared by dispersing the equal volumes of dry MWCNTs and SiO2 nanoparticles in a specified amount of the binary mixture of water/EG (50:50 %vol.). The measurement results at different shear rates showed that the base fluid possessed Newtonian behavior, while all nanofluid samples exhibit a pseudoplastic rheological behavior with a power law index of less than unity (n