Behaviour of Molten Metal Film and Effect of Electromagnetic Force.

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In order to obtain a uniform and stable molten metal film, the shape control function induced by high frequency magnetic field is utilized.Firstly, the falling behaviour of liquid film shaped by a slit nozzle was observed in a water-model experiment by use of a high speed VTR. The Falling liquid is classified into two regions. Namely, one is denoted as the film flow region appearing in the middle part of the falling liquid and the other as the channel flow region appearing in both sides of the film flow region. The eidth of the film flow region decreased continuously with increase in the falling distance. A mathematical model predicting the falling behaviour of the liquid film is developed on the basis of hydrodynamics and is verified by the water-model experimetn.Then, the effect of magnetic field on the falling molten-metal film is studied by the mathematical model taking into account the magnetic pressuer induced by magnetic field. Transverse magnetic field imposed on mercury surface mave and damping behavior was measured by making use of laser beam. It was found that the suppression of wave motion did not depend on field intensity but the gradient of it. A dispersion relation of wave motion. is derived from the theoretical analysis taking into account of the gradient of magnetic field, and is verified by the experimental results.A direct magnetic field imposed virtically to surface of liquid mercury and damping behavior of wave motion was measured by using slit beam. A damping coefficient of wave motion, is derived on the basis of magnetohydrodynamics, and experimental data verifies the theoretical results. Magnetic filed intensity to completely suppress wave motion of molten steel is evaluated by use of the dispersion relation and the damping coefficient derived here.