EFFECTS OF NANOPARTICLES ADDITIVES ON THERMAL CONDUCTIVITY AND VISCOSITY OF ETHYLENE GLYCOL AS AUTOMOBILE COOLANT USING CENTRAL COMPOSITE DESIGN.

ABSTRACT
Nanofluids which are fluids containing nanometer-sized particles which are usually metals or oxides of metals are becoming popular for their enhanced thermal properties as a result of the need to improve heat dissipation by coolants in automobile engines and industrial engines.
The main aim of this study was to investigate the effects of nanoparticles additives on the thermal conductivity and viscosity of a base fluid. The nanoparticles used in this study was prepared from periwinkle shell and the base fluid used was ethylene glycol. Response Surface Methodology using the central-composite model was used to analyze and optimize the effect of three variables: emulsification time, temperature and volume fraction on the thermal conductivity and viscosity of the nanofluid.
From the ANOVA statistical analysis, quadratic model was suggested for both thermal conductivity and viscosity. It was observed that an increase in volume fraction and emulsification time causes an increase in both thermal conductivity and viscosity with volume fraction having a more significant effect. It was also observed that temperature had no effect on the viscosity and thermal conductivity of the nanofluid. Optimization to maximize thermal conductivity and minimize viscosity was carried out to determine the optimal values for the three independent variables. The optimal values gotten were 97.5minutes for emulsification time, 50.08oC for temperature and 0.026 for volume fraction. The corresponding thermal conductivity was 0.319W/m.oC and viscosity was 84.74cP.