COAGULATION OF PARTICLES IN OIL BY AN AC ELECTRIC-FIELD (FUNDAMENTAL EXPERIMENT)

This paper describes an experimental investigation of the coagulation of particles in oil under the action of an a.c. electric field. The in vestigation is carried out to acquire fundamental data to develop an e lectrostatic liquid filter with higher performance. The coagulation pr ocess of spherical silica particles is observed using a video-microsco pe with a CCD (charge coupled device) camera under various conditions and the effects of some mechanical factors such as the strength of the a.c. electric field, the velocity gradient of flow and so on are exam ined. The electric field is applied perpendicularly to the flow and pa rticles are aligned in the same direction as the a.c. electric field b y its action. The experiment shows that a certain frequency of a.c. el ectric field and a certain velocity gradient of flow exist which rende r the rate of coagulation maximum. It is pointed out that an interacti on between the a.c. electric field and the flow field has a significan t influence on the coagulation process.