An experimental investigation of rheological characteristics of non- Newtonian nanofluids

Abstract

Rheological characteristics of Al2O3, CuO and TiO2 nano particles were investigated in oil asthe base fluid at 1 and 2 wt.%. Constitutive relations for non-Newtonian fluid were discussedbased on the power-law model. Measured viscosities of each nanofluid were used to evaluatethe power-law and consistency index. Results indicated that the nanofluid viscosity decreasedby increasing the concentration. Oil showed shear thickening behavior while nanofluids showedshear thinning behavior. An increase in nano-particle concentration caused a decrease in thepower-law index beside an increase in the consistency index. Moreover, the present studyshowed that the effective viscosity of fluids would be decreased by nanoparticle addition atsome wt.% and some shear rates. Furthermore, results showed that the classic models fornanofluid viscosity couldn’t predict their real values of nano fluid viscosity, as the measuredvalues are less than the predicted ones.

Keywords

• nanofluids
• viscosity
• rheological characteristics
• power-law index
• consistency index