Molecular Dynamics Simulation on the Interfacial Interaction between Triglycerides and Microwater in Natural Ester Insulating Oil

Compared with mineral insulating oil, ester oil exhibits the goodness of better degradation, environmental friendliness, and high safety. In this work, the molecular dynamics methods were applied to study the interfacial interaction between triglycerides and microwater in three mixed models of oil-microwater (soybean, rapeseed, and sunflower oil) at same temperatures. Based on the COMPASS force field, the interaction energy, free volume, and mean square displacement of micrwater in three mixed models were calculated from 323 K to 383 K. The results indicate that the water molecules diffusion strengthen with the increase in temperature, while in the soybean oil-water mixture model, the diffusion is the weakest. In addition, the free volume fraction is the smallest in the soybean oil-water model. This study comprehensively compared the water molecules diffusion in three natural ester insulation oil-water mixed models, providing a reliable theoretical basis for subsequent research on natural ester insulation oil.