Dynamic Characteristics of Charged Metal Particles in Insulating Oil under Multi-physics Coupling

The research on the dynamic characteristics of metal particles in insulating oil under the background of multi-field coupling of flow, electricity and thermal is of great significance to explain the micro-discharge and the insulation deterioration of oil. Based on the theoretical models and simulation calculations, we established the time-varying dynamic equation under DC voltage through analyzing the force of particles in oil flow under the multi-field coupling, and used the fourth-order Runge-Kutta method to solve the motion trajectory of metal particles. Moreover, the effects of voltage level, particle size, oil flow velocity, and temperature on metal particle motion characteristics were analyzed. The results show that when the metal particles flow through electric field, the motion trajectory of the particles changes which is affected by the loading voltage, and the particles show an oscillating motion characteristic between the electrodes. This effect becomes more and more obvious with the voltage increasing. With the increase of flow velocity, the frequency of particle oscillation motion between the electrodes decreases, while the temperature causes little effect on trajectory of particles, which can be ignored. In addition, the size of metal particles also has an effect on their trajectories.