Investigation of effect of dam on intermixing during ladle changeover in six strand billet caster tundish

A study has been carried out to find the effect of placing a dam at different positions in a six strand billet caster tundish on the intermixed amount of liquid steel during ladle changeover in the continuous casting process. The experiment was conducted on a one-fourth scale model tundish fabricated with Perspex sheet. Water was used to represent the old grade steel and salted water was used to represent the new grade of steel. Step input tracer concentration study was carried out after attainment of a steady state velocity field and the intermixed amount was calculated from different outlets. Maximum intermixed amount was obtained from the outlet nearest the ladle stream inlet and the minimum was observed from the outlet furthest from the ladle stream. A numerical study was carried out on full scale tundish and it was seen that the numerical and physical experimental results were very close to each other. The numerical investigation was further extended for investigating the effect of a dam placed at different positions on the intermixed amount from the different outlets. It was found that the placement of dams decreased the intermixed amount in most of the cases. Minimum intermixed amount was found at the position when the dam was placed at a dimensionless distance of 0·083 from the inlet to the tundish.