Hydrodynamic Analysis of the Flow inside the Submerged Entry Nozzle

Abstract

The quality of steel produced by continuous casting depends mainly on the characteristics of the liquid steel flow pattern within the mold. This pattern depends on the flow dynamics of the nozzle that is immersed in liquid steel. This work characterizes the fluid dynamics within two separate submerged entry nozzle models with a square cross section bore. The Froude similarity criterion and water as working fluid have been used. The models consist of a square-shaped tube with one inlet and two lateral squared exits at the bottom. To enhance the flow visualization, the models do not have exit ports. Moreover, one of the models has a “pool,” a volume at the bottom, and the other prescinds of it. The geometrical parameters and operational conditions of physical experiments were reproduced in the numerical simulations. The turbulence model used in this work is large eddy simulation (LES) with dynamic k-equation filtering. It was found that transient numerical simulations reproduce the dynamic nature of the internal flow pattern seen in physical experiments. The results show that the flow pattern within the pool nozzle is defined by only one large vortex; on the other hand, in the nozzle, without the pool, the flow pattern achieves a complex behavior characterized by two small vortexes. This study will allow to build nozzles that produce a symmetric, regular fluid flow pattern inside the mold, which leads to improvements on the process such as low energy consumption and finally in cost reductions.

Analysis of a New SEN Design with an Inner Flow Divider

“…We refer to this fluid flow pattern as OAV-behavior (one asymmetric vortex). This behavior was also observed in numerous experimental tests [6,7,[16][17][18]25]. We recognize that an extensive study is required to elucidate the mechanism causing the loss of symmetry of the fluid flow pattern inside the nozzle.…”

“…The numerical simulations presented in the previous section showed that the flow detector produces smooth and symmetric patterns on both exit ports. As was determined in the previous works [16,17], the properties of the jets emerging from the ports are mainly determined by the flow pattern formed at the bottom of the SEN. The results presented in the latter section explored only the interior flow features.…”

“…Previous numerical and experimental studies have shown that initially, symmetric flow develops two similar counterrotating vortexes at the SEN's bottom. However, depending on the presence of SEN's well and its depth, one of the vortexes shortly becomes dominant, suppressing the other [15][16][17][18]. This behavior, in turn, leads to the change of the flow pattern and thus the jet's characteristics.…”

Visualization and measurement of turbulent flow inside a SEN and off the ports

“…As a consequence of the above behavior, the visualization of the process is performed in experimental facilities using water as the working fluid similarity criterion to obtain a scaled model of the system [3]. It is a frequent practice to reproduce the fluid dynamics within the mold using a scaled, physical model because of the reduced geometrical dimensions of the system and ambient temperature to prevent hazardous conditions during the process [4][5][6][7][8][9][10][11][12][13].…”

Recent Advances in Multiphase Flows in Engineering

“…Gonzalez-Trejo et al [5] studied fluid dynamics within a pair of submerged entry nozzle models with a square crosssection bore. ey contemplated water as a working fluid with the Froude similarity criterion.…”