Measurement of Electrophysical Characteristics of Nanofluids Based on Transformer Oil

Several samples of nano-oil with different concentrations of dielectric and conductive nanoparticles are prepared to describe the electrophysical characteristics of nanofluids. Permittivity and conductivity of the nanofluids are experimentally measured. The processed experimental results are compared with the calculated results obtained using the Nielsen formula. The comparative analysis shows qualitative agreement of the calculated and experimental values of permittivity and a significant difference between the experimental and calculated dependences of conductivity on the concentration of particles. Such a difference between the calculated and experimental results is due to the adsorption of ions on the surface of the particles and their subsequent sedimentation. A decrease in the conductivity can be due to a decrease in the number of mobile particles and the fact that they have significantly less mobility compared to ions in the presence of weak electric fields. Additional measurements of the conductivity of nanofluids with particles of silicon dioxide and added oleic acid reproduce the observed decrease in the conductivity.