Effect of Ultrasonic Action on Al<SUB>2</SUB>O<SUB>3</SUB>/Water Dispersion and Thermal Characterization with Convective Heat Transfer

Abstract

Aqueous solution of Al2O3 nanoparticles is dispersed and thermally characterized. Effect of ultrasonic period of action on dispersibility and particle size has been investigated over the concentration of 0.5 vol.% to 1.5 vol.%. Thermal conductivity and convective heat transfer performance of nanoparticle solution have been experimentally studied at different concentrations. Results show the agglomeration of nanoparticles into dilute solution is time dependent and mean diameter of dispersed particle into solution decreases with increasing ultrasonication period. Thermal conductivity linearly increases with increasing the concentration of nanofluids and it was strongly temperature dependent. The enhancement of local convective heat transfer has been achieved about from 27% to 37% by the concentration of 1.5 vol.% of Al2O3 nanofluids where the maximum thermal conductivity was about 5.33% under same concentration.