Nanoparticle Polarization Effect on the Permittivity of the Dielectric Liquid

Abstract

Nanofluids (NFs) are being increasingly used to improve the heat transfer and dielectric capabilities of the electrical equipment and enhance their life expectancy. Preparation of a stable NF and its superior thermophysical and electrical properties is expected to lead to a much lower life-cycle cost of a power/distribution transformer. This paper intends to analyze the effect of polarization of the nanoparticles (NPs) on the improvement of relative permittivity when they are dispersed in TO. To validate the existing theories about it, experiments are carried out to determine the values of the relative permittivity of both the fresh mineral oil (MO) and vegetable oil (VO), and also the MO-NF and VO-NF. The VO used for this study is the pongamia pinnata oil. In this work, different volumetric concentrations of 0.01, 0.05 and 0.1 wt.% of exfoliated hexagonal boron nitride (Eh-BN) NP dispersed in both MO and VO are considered to understand the variation in the permittivity measurements and a comparative analysis is carried out. This study recognizes the effects of using NPs in both MO and VO and how significantly it influences the dielectric behaviour of the liquid. The results show enhanced permittivity for the NFs as compared to the base fluids. The mechanism behind the change in the relative permittivity is understood by the impact of polarization effects in the Eh-BN NPs added to the oil.