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Pastoriza-Gallego et al. Nanoscale Research Letters 2011, 6:221 http://www.nanoscalereslett.com/content/6/1/221 NANO REVIEW Open Access Thermal conductivity and viscosity measurements of ethylene glycol-based Al2O3 nanofluids María José Pastoriza-Gallego, Luis Lugo, José Luis Legido, Manuel M Piñeiro* Abstract The dispersion and stability of nanofluids obtained by dispersing Al2O3 nanoparticles in ethylene glycol have been analyzed at several concentrations up to 25% in mass fraction. The thermal conductivity and viscosity were experimentally determined at temperatures ranging from 283.15 K to 323.15 K using an apparatus based on the hot-wire method and a rotational viscometer, respectively. It has been found that both thermal conductivity and viscosity increase with the concentration. | Pastoriza-Gallego et al. Nanoscale Research Letters 2011 6 221 http www.nanoscalereslett.eom content 6 1 221 o Nanoscale Research Letters a SpringerOpen Journal NANO REVIEW Open Access Thermal conductivity and viscosity measurements of ethylene glycol-based Al2O3 nanofluids María José Pastoriza-Gallego Luis Lugo José Luis Legido Manuel M Pineiro Abstract The dispersion and stability of nanofluids obtained by dispersing Al2O3 nanoparticles in ethylene glycol have been analyzed at several concentrations up to 25 in mass fraction. The thermal conductivity and viscosity were experimentally determined at temperatures ranging from 283.15 K to 323.15 K using an apparatus based on the hot-wire method and a rotational viscometer respectively. It has been found that both thermal conductivity and viscosity increase with the concentration of nanoparticles whereas when the temperature increases the viscosity diminishes and the thermal conductivity rises. Measured enhancements on thermal conductivity up to 19 compare well with literature values when available. New viscosity experimental data yield values more than twice larger than the base fluid. The influence of particle size on viscosity has been also studied finding large differences that must be taken into account for any practical application. These experimental results were compared with some theoretical models as those of Maxwell-Hamilton and Crosser for thermal conductivity and Krieger and Dougherty for viscosity. Introduction Improving the efficiency of energy production and consumption has undoubtedly become one of the most important global problems that will have to be faced during the next decades. Some of the particular concerns related with this main problem include the quantification and control of global climate change due to the emissions of greenhouse gases or the expected decline in global oil production 1 . Considering the rapid increase in energy demand worldwide intensifying heat transfer processes and .
