6533b853fe1ef96bd12ac004

RESEARCH PRODUCT

Application of AC and DC magnetic field for surface wave excitation to enhance mass transfer

subject

description

Abstract Refining the metallic melts and removal of contaminants from the free surface may be sped up by increasing the surface area of mass exchange interface. It is relevant to both the case of volatile impurity evaporation in a vacuum as well as the case of chemical reactions when the continuous crust of reaction products should be interrupted. Previously proposed low-frequency AC magnetic field excitation of intense surface waves is limited by skin-effect. The induced sign-alternating forcing at high dimensionless frequency values becomes dominantly pulsing at considerably higher than unity values, delivering time-averaged stirring without intense surface waves. Superimposing DC magnetic field over AC one produces stronger alternating forcing with the frequency of the AC field. We are reporting an experimental setup which incorporates very high Ampere-winding 50 Hz AC Bitter coil surrounded by a powerful permanent magnet system. Experiments demonstrating surface waves were done at room temperature with liquid Galinstan alloy in two crucibles, corresponding to the cases of relatively high and low skin-effect. In the following work proposed method will be tested in liquid silicon refining process from phosphorus and boron.