1999 Volume 39 Issue 12 Pages 1245-1251
In order to increase an interfacial area for the promotion of mass transfer in refining processes, a new method exciting surface wave on a molten metal has been proposed in the way introducing an intermittent alternating magnetic field with the stepwise change of amplitude. For estimating the mechanism of the wave excitation on a metal surface and the value of an excited interfacial area, the surface wave behavior on a liquid gallium was measured by use of a laser level sensor by changing intermittent frequency, fi, and duty, D. At lower intermittent frequency compared with the natural frequency of a liquid metal, the change in the magnetic amplitude excited surface motion on an equilibrium surface which could have been formed by the continuous imposition of each magnetic amplitude as a result of the balance between an electromagnetic pressure and a static liquid pressure. When the intermittent frequency is adjusted to the neighborhood of the natural frequency, descending of free surface in the wall vicinity takes place accompanying with increase in the magnetic amplitude and excites surface motion. When the intermittent frequency coincides with the natural one, a free surface area increases remarkably.
