DESIGN PARAMETERS TO OBTAIN AL2O3 NANOFLUID TO ENHANCE HEAT TRANSFER

Abstract

The study of nanostructures gained more and more gr ound in the past years due to the acceptable electr ical conductivity, mechanical flexibility and low cost manufacturing potential (m ixing, mechanical stirring, ultrasonication, vacuum chambers).The process of obtaining nanofluids with 0.1%, 0.5% and 1% concent ration of aluminium oxide (Al2O3) was studied by mechanical stirring (in the reactor station - static process equipment fitted w ith a stirring device in order to obtain solutions, emulsions, to make or to activate chemical reactions and physic-chemical operations a nd to increase the heat exchange), vibrations and m agnetic stirring. The selected nanoparticles have an average size of 10 nm and wer e dispersed in base fluids consisting of distilled water and low concentration of glycerin (5.4%, respectively 13%). The samples extr acted during the process were analyzed with the qua rtz crystal microbalance (QCM ‐ modern alternative to analyze the complex li quids from water and copolymers to blood and DNA an d the dynamic viscoelasticity of fluids can be determined), in te rms of homogenization and stability (behavior in ti me). Also, a heat transfer study with the reactor station and a comparison between t he heat transfer of the carrier fluid (consisting o f water and 5.4% glycerin) and the heat transfer of the antifreeze used in solar p anels installations was conducted. This study showe d a decrease of the time consumed with heating the nanofluids and an improve ment of the heat transfer due to the nanoparticles of Al 2O3.