Thermal conductivity enhancement of transformer oil using functionalized nanodiamonds

To efficiently manage the increasing heat generation within the new generation power transformers, it is essential now to develop advanced dielectric nanofluids having high thermal conductivity. We report here the synthesis and characterization of stable high thermal conductivity Newtonian nanofluids using functionalized nanodiamonds in naphthenic transformer oil without compromising its viscosity and electrical insulating property. Functionalized nanodiamonds are dispersed in naphthenic oil, used as standard transformer oil, forming stable suspensions with high shelf life. The electrical resistivity, dissipation factor and viscosity of the base oil is maintained for the nano-oil containing small weight fraction of the filler (0.12 wt%), whereas the thermal conductivity was enhanced by 14.5%.