Mathematical simulation and modeling of steel flow with gas bubbling in trough type tundishes

Flow of steel in a one-strand slab tundish equipped with a turbulence inhibitor (TI) and a transversal gas bubbling curtain was studied using mathematical simulations, PIV measurements and Residence Time Distribution (RTD) experiments in a water model. The use of a bubbling curtain originates two recirculating flows, upstream and downstream at each of its sides. The first one meets, at some point along the tundish length and close to the bath surface, the downstream that is driven by the TI. After, free shear stresses provided by the upstream make the downstream be directed toward the tundish bottom forming a bypass flow. At the other side, in the outlet box, there is strong recirculating flow which impacts the end wall and goes directly toward the outlet. Two-phase flows simulated mathematically matched experimental flow fields measured with PIV measurements. Tundish performance for inclusions flotation is maximized when only the TI is used followed by using only the bubbling curtain. Increases of gas bubbling flow rate increase the mixing processes in the tundish according to the RTD determinations.