Factors affecting the thermal conductivity of dielectric nanofluids for use as alternative fluids in power transformers

The high heat transfer capabilities of dielectric fluids used in power transformers are considered one of the most important properties responsible for increasing the efficiency of these devices, as these oils transfer the heat generated from the internal parts of the transformer to the external environment. The application of nanotechnology in liquid insulators will increase the heat transfer rates through the thoughtful incorporation of nanoparticles (NPs) in these insulating media. Nanofluids (NFs) have higher thermal conductivity compared to conventional insulating oils found in power transformers, which nominates them as promising alternatives in the field of high voltage. This paper focuses on the thermal conductivity capabilities of dielectric nanofluids as well as the analysis of different factors affecting thermal conductivity. It also presents some theoretical models to determine the thermal conductivity of NFs with the possibility of applying these dielectric nanofluids to improve the heat transfer performance of power transformer.