Thermal Modelling of Mineral Oil and Natural Ester Nanofluids

The operating life and efficiency of a transformer depends on the electrical and thermal performance of its insulation system. The present work involves the preparation and thermal characterization of mineral oil and natural ester nanofluids. An electro-thermal analogous model is developed to determine the thermal resistance and thermal capacitance of the unfilled and nanofilled oils. Simulation model of unfilled and nanofilled oils using Comsol Multphysics is developed to obtain the temperature time plot, from which the values of the thermal resistance and thermal capacitance of the unfilled and nanofilled oils are calculated. The simulation results are validated experimentally. It is observed that the thermal resistance and thermal capacitance values of both mineral oil and natural ester obtained from simulation and experiment decrease with the addition of nanoparticles. This indicates an improvement in the heat distribution and dissipation in nanofluids when compared to the unfilled counterparts, rendering them better insulating oils for transformers.