Effect of Basset Force on Non-conductive Particle Motion in Electrically Conductive Fluid under Oscillating Electromagnetic Field

Inclusion removal from a molten steel is essential problem to be solved for high quality steel production. Removal of micron-size inclusions from the molten steel by the conventional inclusion-removal process using density difference between the inclusions and the molten steel is difficult because their rising velocity is not enough for removal in the operating time. Collision and coagulation are useful phenomena to promote rising velocity of the inclusions by increasing their size. Imposition of oscillating electromagnetic field having a function of collision enhancement is one of the promising methods for the inclusion removal. The inclusion motion under imposition of the oscillating electromagnetic field is governed by inertial, viscous and Basset forces. However, effect of the Basset force on the inclusion motion is not clarified. In this study, an experimental model consisting of electrically insulating particles and a conductive and transparent aqueous solution was constructed to clarify the effect of the Basset force on the inclusion motion. Both amplitude of the inclusion motion and phase of inclusion position based on the oscillating electromagnetic force as a phase reference agreed with theoretical prediction under the consideration of the Basset force. Relative error of Al2O3 inclusion motion in the molten steel due to neglect of Basset force was theoretically estimated. Prediction without the Basset force induces serious errors of amplitude and phase of the inclusion motion, which lead to over estimation of collision frequency among inclusions.