On the dependence of the viscosity coefficient of nanofluids on particle size and temperature

The dependence of the viscosity coefficient of nanofluids based on ethylene glycol with SiO$_2$ particles on nanoparticle size and temperature is experimentally studied. The experiments are conducted for nanofluids with an average particle size of 18.1, 28.3, and 45.6 nm. Their volume concentration is varied from 0.2 to 8%. The temperature of the fluid is varied in a range of 20–60$^\circ$C. It is shown that the viscosity of nanofluids heavily depends on particle size: the smaller the particles, the higher the viscosity. On the other hand, the viscosity of all the studied nanofluids decreases with increasing temperature.