ABSTRACT
In this study two important thermo-physical properties of nanofluid: thermal conductivity and viscosity was investigated. Nanofluid has been defined as colloidal of solid particles with sizes lower than 100nanometer. A three variable Box-Behnken design was used to study the effects of volume fraction, temperature and emulsification time on the thermal conductivity and viscosity. Optimization was carried out using Response Surface Methodology (RSM).
The nanofluid (Ethylene glycol and snail shell ash) was prepared by the single step method [that is dispersing the nanoparticle directly in the base fluid (ethylene glycol)].The viscometer was used to measure the viscosity of the nanofluid and an experimental setup containing water bath, thermocouple and magnetic stirrer was used in determining the thermal conductivity of the nanofluid.
The results obtained show that the thermal conductivity increases with increasing volume fraction, with minimal effect on emulsification time and no significant effect on temperature which could be as a result of the particle size and that obtained for the viscosity shows that the viscosity increases with an increase in volume fraction with no effect on emulsification time and temperature.
The optimum thermal conductivity at maximal conditions was obtained at 0.8249 (W/M. K) and that of viscosity at the minimal conditions at 28.5306cP with an emulsification time, volume fraction and temperature at 120seconds, 0.028 and 35.630C respectively.
