SYNTHESIS AND THERMO-PHYSICAL CHARACTERIZATION OF GRAPHENE BASED TRANSFORMER OIL

Transformer oils serve as coolants and an insulation medium to avoid overheating. Due to low thermal conductivity of transformer oils which may result in overheating and hence nanoparticles are introduced to overcome this challenge. In this research, graphene nanoparticles (GNPs) were dispersed in transformer oil at a concentration of 0.01-0.1 wt% respectively. The stability of the graphenetransformer oil nanofluids (GTNFs) is studied using UV-Vis spectrophotometer.Optical microscope is used to study the dispersion quality and the uniformity of clusters formed at different weight fractions qualitatively. Thermal conductivity and viscosity of the samples were measured over a range of temperature from 20-100 °C. The thermal conductivity and viscosity of GTNFs were observed to be strongly dependent on the temperature and concentration of GNPs. The enhancement in thermal conductivity obtained was from 2.63-69.31 % as the temperatures varies from 20-100 °C, for 0.01-0.1 wt% of GNPs. It was also further observed that the viscosities of the GTNFs were reduced by 8.33-23.97% as the temperature rises allowing more convectional heat flow. It is thus concluded that the increase in thermal conductivity and decrease in viscosity as temperature rises enhances the overall performance of the transformer oil.