Transformer oil nanofluids by two-dimensional hexagonal boron nitride nanofillers.

This paper presents some attractive properties of two-dimensional (2D) nanofillers based transformer oil (TO) nanofluids. Nanofluids of 2D hexagonal boron nitride (h-BN) nanosheets in TO show stable dispersion with improved dielectric breakdown strength and superior thermophysical properties like thermal conductivity, viscosity, and stability. A substantial augmentation in AC breakdown voltage (BDV) of TO with h-BN is observed, large compared to the state-of-the-art boron nitride (BN) particles. The enhancement in BDV is clarified by the role played by the larger oil-nanofiller interfacial regions also known as Maxwell-Garnet regions of 2D nanofillers in the context of charge trapping performance. The faster rate of heating and cooling and noteworthy enhancement in thermal conductivity agrees well with Maxwells forecasts. It is explained by the enhanced phonon transfer via the large oil-nanofiller interface of 2D nano additives. Finally, the natural electrostatic repulsion between the h-BN sheets at diluted concentration exhibited enhanced stability both with time and temperature variation compared to its particle counterpart and yielded in high thermal efficiency. Hence, 2D nanofillers are better choices for next generation surfactant free transformer oil nanofluids due to their high surface area, lower filler fraction and enhanced stability. [ABSTRACT FROM AUTHOR]