Dielectric properties of silica based synthetic ester nanofluid

Abstract

This work studies the impact of silica nanoparticles on the dielectric properties of synthetic ester oil. A stable nanofluid is prepared by addition of surfactant. With addition of nanoparticles there is an increment in dielectric constant and decrement in dielectric loss constant. An attempt is made to understand the conduction mechanisms in uniform field and non-uniform electric field configuration by means of analysing the mobility of ions. Under uniform electric field stress (<0.1 kV/mm), by means of conduction current measurement with polarity reversal, the ionic mobility, conductivity, ionic concentration and ionic radius are deduced. There is a reduction in ionic mobility by addition of nanoparticle and surfactant. To understand the conduction mechanisms in high electric field condition, the current-voltage characteristics of the nanofluid are measured. Using this data, apparent mobility due to electrohydrodynamic motion is estimated, giving a lower mobility in the case of nanofluid, which could be the cause of the increased corona inception voltage.