Effect of oxidative ageing on the thermophysical and electrical properties of the nanofluid with statistical analysis of AC breakdown voltage

Abstract

In this study, the prediction of the breakdown probability of a new batch of nanofluid (NF), namely exfoliated hexagonal boron nitride based NF is performed. Weibull two‐parameter model distribution function has been used to predict the AC breakdown voltage (ACBDV) probability percentage at 5, 10, 50 and 63.2% of failure. To verify the effect of ageing on the other allied properties like dielectric dissipation factor, resistivity, interfacial tension, acid number and thermal conductivity of the insulating NF, oxidative ageing test has been performed at three different ageing durations and compared with the existing mineral oil (MO). It is observed that the new batch of NF has the superior properties to be new age insulating oil compared to the MO. A significant enhancement in the ACBDV and thermal conductivity of the NF compared to MO is observed. Hydrophobic nature of the nanoparticle (NP) which has the minimum affinity towards the polar contamination hinders early ageing degradation in the NF. The enhancement in ACBDV of NF is due to the stimulated charge accumulation on the surface of the NP of the NF. The high aspect ratio of the exfoliated NP surface enhances the heat transfer capabilities in the NF.