PHYSICAL MODELLING OF FLOW PATTERN IN 5-STRAND ASYMMETRICAL TUNDISH WITH BAFFLES

The paper is a study of the nature of steel flow in the five-strand asymmetrical tundish situated at CCM No. 1 located in Trinecke Zelezarny, a.s. The plexiglass water model is constructed in a 1:4 geometric scale to the real plant tundish and is located in the Laboratory of Physical and Numerical Modelling at the Department of Metallurgy, FMME, VSB-Technical University of Ostrava. The discussion of results is focused on the evaluation of molten steel behaviour under the conditions of two baffle-type perforated walls inserted into the tundish impact area. The baffles were placed symmetrically between the impact area and the nearest casting strands No. 3 and 4. The technological delay between the discharging of two ladles is not constant. This is why the five different variants of tundish refilling regimes were studied using the physical modelling methods. The method of permanent concentration change (Heaviside unit step) was used to describe the differences between the character of the steel flow under various conditions of the tundish refilling. KCl was used as a marker. The visualization used for a qualitative study of the nature of the steel flow in the tundish was the impulse injection (Dirac pulse) of KMnO4 aqueous solution. The minimum residence times ( min τ ) and moments of 0.5 dimensionless concentration achievement ( 5 . 0 τ ) were acquired from the obtained F-curves. The results gained from experiments were discussed using mathematical and statistical methods. The coefficient of variation was used for homogeneity rate interpretation of steel distribution into individual casting strands.