Heat transfer coefficient and viscosity of alumina-water nanofluids

Abstract

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.Boiling heat Transfer Coefficient of 0.1 vol.% wateralumina nanofluids and the effect of pH value of the solution was studied. It was observed that as the pH value changed from neutral (6.5) to acidic (5), the particle cluster size and solution heat transfer coefficient were affected. The cluster size of the nano-alumina fluid decreased with increasing sonicating time. The flow behavior of the nanofluid for 1 to 4 vol.% concentrations was studied and it was observed that these nanofluids behaved as Newtonian and their viscosity decreased with increasing sonicating time. The decrease in viscosity could be attributed to the fragmentation of the nano-particles and clusters as observed from their microstructure.