Process Parameters Effect Investigations on Viscosity of Water-ethylene Glycol-based α-alumina Nanofluids: An Ultrasonic Experimental and Statistical Approach

Stable alpha-alumina-water-ethylene glycol (WEG) based nanofluids with a low viscosity requirement are preferable for promising engineering applications. Viscosity of nanofluids is a significant parameter that decides the flow characteristics and pumping pressure requirements. In this study, alpha-alumina nanoparticles (spherical morphology with 40 nm) dispersed in WEG mixture in a ratio of 50:50 (v/v) using an ultra-sonication process. Further analysis of the effects of process parameters on the viscosity of prepared nanofluid, including volume concentrations (0.01%-0.2%), temperatures (30-45 degrees C), and sonication times (0-4 h). A decrease in viscosity of 11.36% was observed for 0.2% volume concentration as sonication time increased from 0 to 3 h at a process temperature of 45 degrees C. The viscosity value of nanofluids approaches a stable value at 3 h of sonication. No significant sonication 'null effect' was required for lower concentrations irrespective of the temperature and sonication time, yielding low viscosity. At the same time, clusters were observed at a higher volume concentration under a minimal sonication time (1 h) resulting in a higher viscosity. On the other hand, the viscosity of nanofluid was reduced with the help of an increase in sonication duration and process temperature. Statistical analysis ranks a higher degree to volume concentration of nanoparticles.