Fundamental Investigation of Charge Injection Type of Electrostatic Oil Filter

Abstract

This paper deals with the effects of mechanical factors on the filtration speed of a charge injection type of electrostatic oil filter. The new filter has been proposed by Yanada and his coworkers and it has been demonstrated that the filtration speed can be increased to a great or some degree by injecting charges into oils, but the experimental condition was limited. In this paper, the effects of the number of the projections, the electrode spacing, the applied voltage and the oil temperature on the filtration speed are examined using a simple filter model and various types of oil. In order to discuss the effects of those mechanical factors on the filtration speed, numerical simulation of electrostatic field between electrodes is done and the oil flow caused between the electrodes due to ion drag phenomenon, called the ion drag flow in the paper, is observed using a charge coupled devise (CCD) camera and is analyzed using a particle image velocimetry (PIV) technique. The experiments and numerical simulation make clear the effects of the mechanical factors on the filtration speed. An optimal electrode configuration and operating condition are found out.

Keywords

• electrostatic filter
• lubricating oil
• charge injection
• mechanical factor
• ion drag flow
• electrostatic field simulation
• reuse