Mathematical modeling of inclusion transport and removal in continuous casting tundishes

Three-dimensional mathematical models are currently being used successfully to model liquid steel flow and turbulence behavior in continuous casting tundishes. Traditionally, this information is used to calculate the residence time distribution (RTD) of liquid metal in the given tundish configuration. The RTD curve provides the effectiveness of a tundish to produce cleaner steel in an indirect and qualitative manner. Recently, some computational models have been developed to predict inclusion trajectories and their rate of flotation in a semi-quantitative manner. In the present work, a model that addresses the inclusion transport and removal phenomena from the molten metal has been developed. The model examines three modes (flotation to the surface, coalescence of particles to form larger inclusions, and sticking to the solid surfaces) of inclusion density reduction from molten steel in the tundish. The effect of various flow control devices, such as dams, weirs and baffles with holes on each of these inclusion reduction modes was investigated and their inclusion removal efficiencies were compared. The role of different flow control devices in producing cleaner steel has been discussed.