Volume 9, Issue 5 (May 2012)
Thermal Conductivity and Rheological Behaviour of Al-alloy Dispersed Ethylene Glycol Based Nanofluids
Al-alloy (Al-5 wt. %Zn and Al-5 wt. %Si) nanoparticle dispersed (0.01 − 2.00 vol. %) ethylene glycol based nanofluids are prepared by a two-step process. Prior to dispersing in ethylene glycol by magnetic stirring and ultrasonication the Al-alloy nanoparticles synthesized by mechanical alloying are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area diffraction (SAD), and energy dispersive spectroscopy (EDS) to analyze the identity, size, shape, and purity of the powder. A maximum thermal conductivity enhancement of 16 % for Al-5 wt. %Zn and 13 % for Al-5 wt. %Si dispersed nanofluids are observed at 0.1 vol. % of nanoparticle concentrations. Rheological studies of nanofluids show interesting findings as the viscosity of both types of nanofluids are observed to exhibit values lower than that of base fluid at lower concentrations and higher at higher concentrations. Maximum enhancement of viscosity up to 180 % for Al-5 wt. %Si and 120 % for Al-5 wt. %Zn dispersed nanofluids are observed at 2.0 vol. % concentration.