Experimental characterization and modeling of thermophysical properties of nanofluids at high temperature conditions for heat transfer applications

• Water-based SiO2, Al2O3 and CNT nanofluids have been prepared and characterized.
• Measurements of thermal conductivity, viscosity, specific heat and stability
• Measurements were carried out at different temperatures up to 80 °C.
• Evolution of physical properties with solid content has been modeled.

The use of suspended nanoparticles in a base fluid has been practiced in the last years to increase its heat transfer capabilities. In this work, water based nanofluids of silica, alumina and carbon nanotubes were characterized regarding its later use in heat transfer applications. Well dispersed nanofluids were prepared at different volume fractions (up to 5 v%) by dispersing the powder into the base fluid or by diluting commercial nanofluids acquired in suspension form. The thermal conductivity, the specific heat and the viscosity of all the prepared nanofluids were measured in order to optimize the Prandtl number and the heat transfer performance, at high temperature conditions (up to 80 °C). Available models for these variables have been used to predict experimental data and the suitability of each one for the different sort of tested nanofluids has been obtained. Finally, the stability of the nanofluids was also studied through the evolution of the amount of light scattered by the sample during a period of time.

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