Synthesis of Al2O3-Cu/water hybrid nanofluids using two step method and its thermo physical properties

In the present work, Al2O3-Cu hybrid particles have been synthesized by hydrogen reduction technique from the powder mixture of Al2O3 and CuO in 90:10 weight proportions obtained from a chemical route synthesis. Al2O3-Cu/water hybrid nanofluids with volume concentrations from 0.1% to 2% were then prepared by dispersing the synthesized nanocomposites powder in deionised water. The experimental results have shown that both thermal conductivity and viscosity of the prepared hybrid nanofluids increase with the nanoparticles volume concentration. The thermal conductivity and viscosity of nanofluids have been measured and it has been found that the viscosity increase is substantially higher than the increase in thermal conductivity. The experimental measurement of thermal conductivity showed a maximum enhancement of 12.11% for a volume concentration of 2%. The experimental results have been compared with the classical theoretical models available in literature. (C) 2011 Elsevier B.V. All rights reserved.