Systematic Experimental Study of the Viscosity of Nanofluids

Abstract

The systematic experimental investigation of the viscosity of more than 30 different nanofluids was carried out. The investigated nanofluids were prepared based on distilled water, ethylene glycol and engine oil containing nanoparticles Al₂O₃, TiO₂, ZrO₂, CuO, Fe₂O₃, and Fe₃O₄, as well as nanodiamonds. The nanoparticle volume concentration ranged from 0.25 to 8%. The size of nanoparticles varied from 5 to 150 nm. The temperature changed from 25 to 60 °C. The effect of the nanoparticle concentration and size, as well as the base liquid properties, temperature, and additives of stabilizing surfactants on the viscosity of nanofluids were investigated. In particular, the factors affecting the rheology of nanofluids were studied. It was found that the viscosity of nanofluids depends on the material of the nanoparticles. It is shown that with decreasing nanoparticle size, the viscosity of nanofluids increases. In contrast to the classical microscopic suspensions, the relative viscosity of nanofluid depends on the viscosity of the base liquid. In general, the higher is the viscosity of the base fluid, the higher is the increment of the nanofluid viscosity. It was found, that the rheological behavior of the Newtonian nanofluid can become non-Newtonian with the growth of the volume fraction of nanoparticles and decrease of their size. At very high nanoparticle concentration the relative viscosity of nanofluid depends on temperature and characterized by hysteresis, i.e. the viscosity of nanofluid during heating and cooling differs significantly.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was funded by RFBR (Project No. 17-01-00040 and No. 17-58-45023). The investigation of rheology was funded by Russian Science Foundation (project No. 17-79-20218). The investigation of nanodiamonds was supported by the Ministry of Education and Science of Russian Federation Government contract with Siberian Federal University.

Notes on contributors

Andrey V. Minakov

Andrey V. Minakov is an associate professor of the Department of Thermal Physics, Siberian Federal University, Krasnoyarsk, Russia. He received his Ph.D. from Siberian Federal University, Russia, in 2008. He has authored and coauthored over 100 publications in international journals and conferences. His current research focuses on experimental and numerical study of heat and mass transfer processes in nanofluids and microhydrodynamics.

Valery Ya. Rudyak

Valery Ya. Rudyak is a doctor of science, professor, and head of the Department of Theoretical Mechanics, Novosibirsk State University of Architecture and Civil Engineering, Novosibirsk, Russia. Included in the top 100 most cited mechanics of Russia. An active member of several international communities. Specialist in the field of the kinetic theory of gases, non-equilibrium statistical mechanics, physics of dispersed systems.

Maxim I. Pryazhnikov

Maxim I. Pryazhnikov is currently working as a junior researcher at the Siberian Federal University, Krasnoyarsk, Russia. He received his Master’s Degree in the department of thermal physics from Siberian Federal University, Krasnoyarsk, Russia, in 2013. His current research focuses on thermophysical, rheological, acoustic properties of suspension and emulsion.