Effect of temperature and mass fraction on viscosity of crude oil-based nanofluids containing oxide nanoparticles

In this study the effects of various oxide nanoparticles on viscosity of crude oil-based nanofluid were investigated. Furthermore, the effects of temperature and mass fraction of TiO2, NiO, Fe2O3, ZnO and WO3 nanoparticles on relative viscosity of nanofluid were studied. The morphology and stability of nanoparticles were characterized by using TEM and DLS analysis. The results of characterization showed that the average nanoparticle diameter ranged from 10 to 40 nm for different oxide nanoparticles. Also the results of experiments showed that with the increment of temperature the ratio of the nanofluid viscosity to basefluid declined. Moreover, for nanofluid containing nanoparticles with higher density the relative viscosity increases significantly and with the temperature enhancement higher than 50 degrees C the values of relative viscosities are less than unity declaring a lower viscosity of nanofluids with respect to basefluid. Finally, an empirical correlation comprising nanoparticle density, temperature, and mass fraction was obtained based on regression analysis for estimation of relative viscosity of nanofluid. The results exhibited that the deviation of the correlation from the experimental values was mostly less than 20% and the results of other researchers agree well with the data predicted by the correlation of this study. (C) 2017 Elsevier Ltd. All rights reserved.