Abstract
Removal of non-metallic inclusions from a molten metal using buoyancy force acting on them has been carried out in steel industry. However, the productivity is restricted by rising velocity of the inclusions in the molten metal. Collision and coagulation of the inclusions promotes their rising velocity by increasing their apparent size because the rising velocity is proportional to the square value of inclusions diameter. Utilization of an oscillating electromagnetic field has a potential to enhance the collision among the inclusions and to promote their rising velocity. However, quantitative prediction of the collision enhancement effect of the oscillating electromagnetic field has not been investigated. In this study, the collision enhancement effect of the oscillating electromagnetic field on the collision among non-conductive particles in a conductive liquid has been theoretically investigated. Collision among the particles is enhanced over a critical electromagnetic volume force. In the case when the friction drag force becomes the dominant resistance force of the particle motion, the critical electromagnetic volume force is smaller than those in the case when the Basset force or inertial force becomes the dominant resistance force. And this case is desirable for the collision enhancement because the collision enhancement effect increases with decrease of the critical electromagnetic volume force. Imposition of the oscillating electromagnetic field enhances the collision among Al2O3 inclusions in the molten steel, especially among small inclusions, under the clam flow condition.
