Abstract

γ-Al2O3 nanoparticles were dispersed in 20 % wt. aqueous solution to prepare four types of non-Newtonian nanofluids. Rheological characteristics of the base fluid and nanofluids with various nanoparticle volume concentrations were measured. Results show that all nanofluids as well as the base fluid exhibit pseudoplastic (shear thinning) behavior. The rheological characteristics of nanofluids and those of the base fluid are functions of particle concentrations. Electrical conductivity show polynomial behavior at a temperature of 25°C for different concentration fluids. The flow characteristics show rheopectic behavior according to concentration of Al2O3 with highly non-Newtonian characteristics at lower shear stresses. Rheological characteristics suggest that at room temperature viscosity is higher for higher concentration nanofluids.

Keywords: Electrical conductivity, experimental, non-newtonian, power law, rheological behavior