Thermal conductivity and viscosity optimization of nanodiamond-Co3O4/EG (40:60) aqueous nanofluid using NSGA-II coupled with RSM

In this study, both minimizing the viscosity and maximizing the thermal conductivity of ND-Co3O4/EG (40:60) aqueous nanofluid have been considered. The response surface method has been conducted to achieve correlations of nanofluid's thermal conductivity and viscosity in terms of solid volume fraction and various temperatures by using the empirical data. The attained correlation has a regression coefficient of > 99.4%. Approximating correlations are utilized as fitness functions of the NSGA-II optimization algorithm. It is ascertained by the optimization result that both the maximum thermal conductivity and minimum viscosity happen at the highest temperature. This shows the optimization performance's validity. Ultimately, the Pareto front and its corresponding optimal points are made available in terms of the solid volume fraction.