Heat Flow and Inclusion Behaviour in a Tundish for Slab Casting

Abstract

An analysis of metal flow, heat transfer and inclusion flotation in a tundish is carried out. Computations are presented to illustrate the significant role of the thermal natural convection current in mixing the upper and lower layers of steel when substantial heat losses take place from the liquid steel's surface and/or the sidewalls of the tundish. The use of flow modification devices is shown to be helpful in further reducing effluent density level of inclusions at the intermediate to larger size ranges. However, small inclusions (e.g. < 40 μm) are not readily removed, with or without flow modifications, on account of their low Stokes rising velocities. It is also shown that sloping sidewalls are helpful in removing inclusions and reducing thermal natural convection effects, but lead to slightly higher temperature losses in the metal. Scientific visualization of the results is also carried out, and these prove critical for interpreting the massive amounts of data generated by such complicated computations. In particular, the spiral looping and stochastic nature of flows, not evident in two-dimensional representations, are clearly revealed in animation sequences.