Investigation into effective viscosity, electrical conductivity, and pH of γ-Al2O3-glycerol nanofluids in Einstein concentration regime

Abstract

Nanofluids have shown great promise in the design of heat transfer equipment. In this study, the viscosity of γ -Al2O3 glycerol nanofluids was investigated in the Einstein’s volume concentration regime (≤2%). The effect of temperature, volume concentration, electrical conductivity, and pH was investigated at a constant shear rate. The nanoparticles were 20–30 nm. γ -Al2O3 glycerol nanofluids samples were prepared, followed by ultrasonication at two different time period of 3 and 6 h. The effects of volume concentration on the effective viscosity, electrical conductivity, and pH were all monitored in the temperature range of 20–70◦C. It was found that classical models underpredicted the experimental data while an empirical model overpredicted the experimental data. Furthermore, the electrical conductivity and pH were significantly affected by temperature and volume fraction.