Experimental investigation of viscosity and specific heat of silicon dioxide nanofluids

Results of an experimental investigation into the viscosity and specific heat of silicon dioxide (SiO₂) nanoparticles with various diameters (20, 50 and 100 nm) suspended in a 60:40 (by weight) ethylene glycol and water mixture are presented. Nanofluids with particle volume percentages ranging from 0 to 10% were examined. Viscosity experiments were carried out over wide temperature ranges, from -35 to 50degC, to demonstrate their applicability in cold regions. The nano- particle diameter effect on the rheology of the SiO₂ nanofluid is explored. Non-Newtonian behaviour was observed for the particle volume concentrations of these nanofluids at sub-zero temperatures. A new correlation was developed from experimental data, which related viscosity with particle volume percent and nanofluid temperature. The specific heats of the SiO₂ nanofluids for various particle volume concentrations are presented.