Experimental investigation on viscosity of water-based Al2O3 and TiO2 nanofluids

• Published in: Rheologica acta 2015-05, Vol.54 (5), p.411-422
• Main Authors: Jarahnejad, Mariam, Haghighi, Ehsan B., Saleemi, Mohsin, Nikkam, Nader, Khodabandeh, Rahmatollah, Palm, Björn, Toprak, Muhammet S., Muhammed, Mamoun
• Format: Article
• Language: English
• Subjects: Al2O3; Aluminum oxide; Characterization and Evaluation of Materials; Chemistry and Materials Science; Complex Fluids and Microfluidics; Concentration; Food Science; Materials Science; Mechanical Engineering; Nanofluid; Nanofluids; Nanoparticles; Original Contribution; Particle size; Polymer Sciences; Soft and Granular Matter; Surfactant; Surfactants; Temperature; TiO2; Titanium dioxide; Viscometers; Viscosity
• ISSN: 0035-4511; 1435-1528; 1435-1528
• DOI: 10.1007/s00397-015-0838-y

This article investigates the influence of temperature, concentration, and size of nanoparticles, and addition of surfactants on dynamic viscosity of water-based nanofluids containing alumina (Al 2 O 3 ) and titania (TiO 2 ) nanoparticles. Two viscometers, a capillary and a falling ball, were used for the measurements in the temperature range of 20–50 °C and the particle concentration of 3–14.3 wt.%. The results indicate that the viscosity of nanofluids is reduced by increasing the temperature, similar to their base fluids. Moreover, surfactants, which are used to improve the shelf stability of nanofluids, most likely increase their viscosity. The correlations derived from the linear fluid theory such as Einstein and Batchelor, especially for solid concentration above 1.5 wt.% are not accurate to predict viscosity of nanofluids, while the modified Krieger-Dougherty equation estimates viscosity of nanofluids with acceptable accuracy in a specific range of solid particle size to aggregate size.