Importance of the Lorentz force in electrically heated glass melts

Abstract

In all computations of the flow velocities and temperature distributions in electric glass melts the electromagnetic Lorentz force has been neglected. This force is caused by the interaction between electric current density and the magnetic flux density in the region around electrodes. For some examples of real glass melting furnaces the necessity of including the Lorentz force into flow modelling was demonstrated. Some problems, e.g. the thermal stability of the batch layer in furnaces with top electrodes and the residence-time distribution of tanks with horizontal electrodes, cannot be explained and interpreted realistically if this second driving force besides the buoyancy is neglected. Moreover, the method of physical modelling of the electrically heated glass melts remains doubtful as long as the similarity criteria also for the Lorentz force cannot be fulfilled.