Predicting the effective viscosity of nanofluids based on the rheology of suspensions of solid particles

Abstract

The development of nanofluid as an innovative class of thermal fluid subsequently inspired use in their engineering applications. As a result, the necessity of experimental work to determine the thermophysical properties of nanofluids affecting heat transfer such as specific heat capacity, viscosity, thermal conductivity and density. Theoretical models are used in numerical studies of engineering applications to calculate thermophysical properties. This study intends to develop a new correlation for calculating the effective viscosity of nanofluids. In the model, we considered an effect of interfacial layer on the nanoparticle, the interfacial layer on nanoparticle works as a solid like layer in between the base fluid and nanoparticle surface. When nanoparticles are suspended in the base fluid, Brownian motion occurs due to the relative velocity of the base fluid and nanoparticles, which is also incorporated in this model. The correlation developed successfully express in outcome advance the viscosity of a variety of nanofluids, (Al2O3, Fe, hexagonal boron nitride (hBN), ZnO)-Ethylene Glycol, (Al2O3, hBN, SiC)-Ethylene Glycol Water mixture, (CuO, Al2O3, Fe3O4, TiO2, hBN, Graphite, Single-wall carbon nanotube (SWCNT))-water, (Fe3O4)-Toluene. The new correlation was derived from 501 viscosity values of nanofluid, 75% of them are within the correlation coefficient 0.78–1 and mean deviation less than 5%.