Abstract
A computational fluid dynamics model on a joule-heated glass melter, which is used for the vitrification process of high-level liquid waste, has been developed to simulate the operation of actual melters. Electric field simulation is coupled with the thermal and flow field calculation to investigate the effects of the joule-heating on the buoyancy-driven flow of the molten glass. The melter is operated in a cyclic sequence including a bottom-heating phase, a drain phase and a bottom-cooling phase. In order to estimate the transient behavior of actual melters, unsteady simulations for several tens hours are necessary. It is found that there is non-uniformity of the heating at the bottom of the melter during bottom-heating phases. It is generated by the asymmetrical electric current distribution due to the arrangement of the electrodes. The temperature distribution at the bottom, however, is kept almost symmetrically due to the mixing effect by the natural convection of the glass. Computational results are compared with experimental data obtained by actual operations of a prototype melter. The temperature distribution and electric resistance between electrodes predicted by the simulations indicate that the characteristics of the simulated melter show good agreements with the actual melter.
