Improvement of liquid-based electrical insulation via electrohydrodynamic flow control

In liquid dielectrics, smart use of charge injection to improve electrical breakdown strength has been demonstrated in previous works. The bottleneck of this approach is the controllability of charge injection. The objective of this work is to numerically study a new design of charge injecting electrodes using electrohydrodynamic flow. In our needle-plane configuration, the needle electrode has a nozzle connecting its interior to the outside, both filled with the same dielectric liquid. The strong inhomogeneous electric field is able to drive liquid flow through the nozzle, during which the liquid jets will be carrying the charge with the same sign as the electrode. In this work, we build the electrohydrodynamic model and develop a numerical program to simulate this process. Our model couples incompressible flow with electric field and current continuity equations. The steady-state simulation results confirm that the hollow electrode with microchannels can effectively inject homocharges which enhance the electrical conductivity and lower the electric field in the region near the electrode surface. The flow may also help circulate the liquid and drive impurities away from electrode surface area. We explore a new way to improve electrical breakdown threshold of materials, which may have impact on the electric power industry and other technologies.