Solidification model for continuous steel casting with focus on flow modelling

In continuous casting of steel, the slow solidification results in a flat increase of the solidified shell thickness. Thus, the liquid core reaches up to 20 m into the strand. In most of the numerical flow simulations of continuous steel casting, the solidification process and its influence on the flow are completely neglected. Furthermore, only the upper part of the liquid core is simulated, which requires the introduction of an unphysical boundary condition at the lower bound of the simulated domain. On the other hand, the flow of the liquid steel in numerical solidification simulations is often not considered because of the complexity of solidification models. In this paper, a model that considers the shape of the solidification front in the flow simulation as well as the loss of material through the solidification front is presented. Therefore, the shell thickness has to be known a priori from theoretical or empirical results. Thus it is possible to model a great part of the liquid core inside the strand with respect to inclusion behaviour and variations of the solidified shell thickness due to the flow. Applications to intermediate, thick and thin slab casters as well as round bloom casters will be described.