Speaker
Description
Mass transfer between liquid steel and slag is frequently encountered in the steelmaking processes: for composition adjustment such as desulfurization or dephosphorization, but also for lubrication of continuous casting mold, since the slag viscosity has a major effect and is mainly depending on the thermodynamic equilibrium between the phases. To predict the composition of both the slag and the steel, the local description of the flow at the interface between the two phases is needed. The paper describes some mechanisms to better understand the mass transfer. A water model with oil layer at the top and air stirring is used to visualize the interface behavior and make the link between the hydrodynamics and the global mass transfer. A CFD model is presented. It includes water, oil and air phases. It allows a very precise description of the boundary layers between the two fluids (water/oil), for both momentum and species concentration, and gives a unique insight into the local mass transfer. A key result concerns the prediction of the mass transfer and the very heterogeneous distribution of the mass transfer coefficient along the interface: the internal side of the open eye contributes mainly to the mass transfer. A methodology to cope with the industrial configuration is proposed.