Thermal conductivity behavior of yttria nanofluids

In this paper the effect of nanoparticle concentration and temperature on the thermal conductivity of Yttria- Ethylene glycol nanofluid has been investigated. In addition, the effect of aging on the viscosity and the thermal conductivity of these nanofluids also have been studied. The nanofluids were prepared by two-step method, and particle size distributions were characterized using acoustic spectroscopy. It was found that the thermal conductivity of Yttria nanofluids increases beyond the classical Hamilton-Crosser model. Moreover, the enhancement in the thermal conductivity of this nanofluid showed high temperature dependence behavior. For instance at 3.0% by volume particles loading, the thermal conductivity enhancement increased from 16.6% at 26 0C to 27.0% at 59 0C, making these nanofluids attractive and effective for cooling systems that operates at high temperatures. Finally, time dependent viscosity and thermal conductivity measurements showed stable behavior for 16 days of study demonstrating the good stability of these nanofluids.