Mold Flow Modeling of ArcelorMittal Riverdale and POSCO Thin Slab Casters

摘要

Liquid steel flow in a continuous casting machine is critical due to its effect on many phenomena related to steel quality and castability such as the transport of superheat, meniscus freezing, the transport of inclusions, transient waves and fluctuations of the meniscus, and crack formation. [1-3] The flow in the mold is usually very complex and induces fluctuations at various frequencies. Modeling using both experimental and computational techniques is a common approach to characterize the flow.For that purpose, experimental and computational mold flow models were developed for ArcelorMittal Riverdale and POSCO thin slab casters. Full-scale water model equipped with Particle Image Velocimetry (PIV) and URANS (Unsteady Reynolds Averaged Navier Stokes) CFD (computational fluid dynamics) models were utilized. A very good agreement between the models was reached. CFD models were developed for both the water model and the thin slab caster separately to accommodate different boundary conditions. The differences in boundary conditions include the following: solidified mass of liquid steel, shell formation, casting speed, and bottom effect. All these helped to understand and to quantify possible variation in mold flow structures between water model and real caster. Applicability of water modeling for thin slab casters was discussed. Different casting conditions including different submerged entry nozzle (SEN) designs were also evaluated. In addition, a new equation that uses the results of transient CFD models was derived to predict the average mold level fluctuation.