Study of Nonlinearity, Activation Energy, and Temperature Effect on Al₂O₃ and TiO₂ Nanoparticle-Based Mixed Oil Characteristics by Dielectric Spectroscopy

This article investigates the dielectric properties of mixed oils [i.e., blending of mineral oil (MO) and vegetable oil (VO)] and their nanofluids at different temperatures by time- and frequency-domain spectroscopy (FDS). Semiconducting-type nanoparticles, TiO2 (titania), and insulating-type nanoparticles, Al2O3 (alumina), are selected for dispersing within mixed oils to prepare mixed oil-based nanofluids. The quality of the prepared samples with different oils is investigated by comparing the corresponding experimental results obtained through ac breakdown voltage (BDV), viscosity, and dielectric spectroscopy. From time-domain spectroscopy, nonlinearity and activation energy are estimated for those prepared samples. Thereafter, a statistical regression model is proposed to investigate the temperature dependency of the dielectric parameters such as real part of complex permittivity and tan $\delta $ . BDV can be enhanced up to 27.13% with dispersion of TiO2 in the mixed oil. Again, by dispersing Al2O3 in mixed oil, viscosity and nonlinearity in the conduction current can be reduced nearly 34% and 54%, respectively, whereas activation energy can be enhanced by 22.7%.