DESIGN PARAMETERS TO OBTAIN AL2O3 NANOFLUID TO ENHANCE HEAT TRANSFER

Andreea Kufner

Abstract: The study of nanostructures gained more and more ground in the past years due to the acceptable electrical conductivity, mechanical flexibility and low cost manufacturing potential (mixing, mechanical stirring, ultrasonication, vacuum chambers).The process of obtaining nanofluids with 0.1%, 0.5% and 1% concentration of aluminium oxide (Al2O3) was studied by mechanical stirring (in the reactor station - static process equipment fitted with a stirring device in order to obtain solutions, emulsions, to make or to activate chemical reactions and physic-chemical operations and to increase the heat exchange), vibrations and magnetic stirring. The selected nanoparticles have an average size of 10 nm and were dispersed in base fluids consisting of distilled water and low concentration of glycerin (5.4%, respectively 13%). The samples extracted during the process were analyzed with the quartz crystal microbalance (QCM – modern alternative to analyze the complex liquids from water and copolymers to blood and DNA and the dynamic viscoelasticity of fluids can be determined), in terms of homogenization and stability (behavior in time). Also, a heat transfer study with the reactor station and a comparison between the heat transfer of the carrier fluid (consisting of water and 5.4% glycerin) and the heat transfer of the antifreeze used in solar panels installations was conducted. This study showed a decrease of the time consumed with heating the nanofluids and an improvement of the heat transfer due to the nanoparticles of Al2O3.

Keywords: nanopowder, mechanical stirring, cluster, QCM, stability, sedimentation

DOI: https://doi.org/10.15623/ijret.2013.0209002