Using design of experiment via the linear model of analysis of variance to predict the thermal conductivity of Al2O3/ethylene glycol-water hybrid nanofluid

In this paper, the thermal conductivity (knf) of the Al2O3/Ethylene Glycol -Water nanofluid is measured. MATLAB software is used to fit a nonlinear function, and the analysis of variance (ANOVA) is implemented to determine the effect of temperature and volume fraction of nanoparticles (φ) on extracting the residuals and knf. In the experimental part, various combinations of temperatures (from 30 to 60 °C) and volume fractions (fromφ = 0.15 up to 1.3%) are examined, and then the obtained data are analyzed using MINITAB software. The results show that the knf is highly dependent on φ and less dependent on temperature. By changing the φ from 0.15 to 1.3%, the thermal conductivity increases around 40%. In contrast, increasing the temperature from 30 to 60 °C will increase the knf by almost 10%. Also, the results show that the thermal conductivity slope is lower at φ < 0.75%, and this rate increases drastically for higher volume fractions. The obtained results, especially the fitting function, are useful for designing and optimizing systems using nanofluids as a working fluid in heat exchangers or energy systems.