Instability analysis of the surface of molten metal under high frequency electromagnetic fields

Abstract

A high frequency electromagnetic field (HFEMF) that is applied to the surface of a molten metal is able to generate a Lorentz force on the surface of the molten metal. This force can be used to seal the molten metal leakage without contact, which makes the quality of metal products purer and the seal system used perform longer. To make this technique possible, it is required to analyze the surface shape and the surface instability when HFEMF is applied to the molten metal surface. It is known from experiment with various kinds of molten metal that the fluctuation of the surface occurs under the applied HFEMF. This fluctuation becomes stronger as the HFEMF is increased. The fluctuation is strongly connected to the instability criteria of the surface. This research has been carried out to make it clear how the HFEMF causes the surface fluctuation of the molten metal, and how it determines the surface shape and stability region. Also, the effects of gradient of HFEMF and DC magnetic field have been investigated.