| In the continuous casting process, the tundish not only serves as an intermediate buffer, but it also acts as a useful reactor for liquid steel refining. Modern tundishes are now designed to carry out different metallurgical operations, such as inclusion separation and flotation, alloy trimming, calcium doped inclusion modification, and thermal homogenization. To carry out such operations effectively, fluid flow inside a tundish plays an important role. It is now a proven fact that the insertion of different types of flow modifying devices can alter flow patterns within the tundish and thus affect the performance of the tundish significantly. Due to adverse operating conditions, direct experimental investigations are difficult to carry out. For that reason, physical and mathematical modeling is predominantly used to study tundish performance. Parameters like 'Residence Time Distribution' (RTD), tracer dispersion, velocity distribution, inclusion separation, etc. were mostly used to study and predict the performance of a tundish. Slag entrainment, though, is a vital problem during ladle changing that has been given less attention. In this research, it is intended to form a physical and mathematical modeling framework, to study and predict the performance of a 12 t, delta shaped, four strand, billet casting tundish. A full scale water model was studied both physically and mathematically. The phenomenon of slag entrainment occurring during a ladle changing operation was used as the key parameter to assess tundish performance. The amount of slag entering the 'Submerged Entry Nozzle' during a ladle change was measured to quantify the performance of different flow modifying arrangements. It is believed that the results of tests carried out under transient conditions can give a fairly good idea about tundish performance at steady state. To strengthen this belief, mathematical modeling of inclusion separation and residence time distribution at steady state was also carried out and trends in the results were compared. The tracer dispersion study was also carried out, using both physical and mathematical modeling. Additionally, non-isothermal mathematical and physical modeling experiments were also carried out to study the effect of temperature changes in the entering flow of liquid steel, using the full scale water model-analogue. |
