Ethylene glycol-based nanofluids: machine learning predictions for improved solar thermal performance
摘要
The experimental data were used to predict equations for the dynamic viscosity and thermal conductivity of six nanofluids employing various machine learning methods. Nanoparticles were oxidized multi-walled carbon nanotubes (MWCNT) and surfactant-assisted MWCNT, dispersed in water and ethylene glycol (EG) ratios as 0:100, 10:90, and 20:80. The data were collected for concentrations of 0.125, 0.25, and 0.5 mass% and temperatures of 50–70 °C. This study applies seven machine learning methods: the Ordinary Least Squares (OLS), the Huber regression, the Decision tree regressor, the AdaBoost regressor, the Theil-Sen regressor, Random forest (RF), Support vector machine (SVM) in the linear and the polynomial formation independently reach the best R-squared (R2). Using the EG temperature and the EG thermal conductivity, the models and the created formulas for the thermal conductivity of the EG/H2O (90:10) and thermal conductivity of the EG/H2O (80:20). The best R2 for making the formula and model to the EG/H2O (90:10) thermal conductivity, respectively, are 0.995, 0.999 reached by the Theil-Sen regressor and the RF and SVM (kernel = RBF) regressors in linear formation. For the EG/H2O (80:20), thermal conductivity is 0.992 and 0.998, respectively, reached by the OLS (polynomial formation) and the RF (linear formation) regressor. The EG + 0.5% oxidized MWCNTs temperature and thermal conductivity are the base for creating the formula and model for the EG/H2O (90:10) + 0.5% oxidized MWCNTs thermal conductivity, and the EG/H2O (80:20) + 0.5% oxidized MWCNTs thermal conductivity, the R2 are, respectively, 0.996 and 0.999 in polynomial and the linear formations reach by the OLS and the RF regressor, and 0.962 and 0.998 in the polynomial and the linear formations by the OLS (for formula) and the AdaBoost and the RF (for model). For reaching the dynamic viscosity of the EG/H2O (90:10) and the EG/H2O (80:20) using the EG temperature and dynamic viscosity, and the best R2 results for building formula and model, respectively, are 0.998 and 0.999 in polynomial and linear formation by the OLS and the RF, and 0.999 and 0.999 by the Theil-Sen regressor and the RF regressor.