Measurement and Numerical Simulation of Flow and Electric Fields in Charge Injection Type of Electrostatic Oil Filter

This paper presents experimental and numerical simulation results of the flow and electric fields in a two-dimensional model of charge injection type of electrostatic oil filter. A previous work has shown that flow is generated from the tips of the projections of the emitter electrode towards the smooth electrodes because of ion drag phenomenon and that the flow may detach part of the contaminant particles captured on the smooth electrodes and may be the principal cause of the saturation of the filtration speed at higher applied voltages and oil temperatures. In order to minimize the bad influence of the ion drag flow on the filter performance, it is important to be able to predict the flow in filters of various configurations by numerical simulation. Numerical simulation results of the flow field are compared to experimental results. In addition, electric potential distribution is measured and is compared between experiment and simulation. It is shown that the flow fields obtained by numerical simulation agree relatively well with measured ones. It is expected that the numerical simulation contributes to designing a filter with a better performance.