A Numerical Analysis of the Fluid Flow in a Slab Mold Considering a SEN with Real Clogging and with Symmetrical Reductions

Nozzle blockage has been a critical issue for productivity and product quality since the introduction of continuous casting. Despite numerous studies on the subject, the problem persists, affecting steel production. This detrimental phenomenon causes changes in the internal nozzle geometry and severe wall irregularities that are neither symmetrical nor uniform. A common approach to studying the complex internal shape of clogged nozzles is considering nozzles with symmetrical transversal area reductions. Therefore, this study aims to quantitatively evaluate the effects of using realistic submerged entry nozzle (SEN) clogging geometries on the fluid dynamic behavior of molten steel inside the SEN and the mold and is compared to simplified symmetric reductions. A three-dimensional mathematical simulation based on the Navier–Stokes equations, the standard k − ε turbulence model, and the Volume of Fluid (VOF) method was used. The main findings indicate that symmetric reductions can only provide a qualitative prediction of the results, such as increased velocity and asymmetries at the meniscus bath level, but with errors that can reach up to 25%. Symmetric reductions fail to accurately capture the fluid dynamics inside the nozzle and the mold and should therefore be used with caution in studies that require precise flow characterization near the nozzle walls.