Recent Developments of a Numerical Model for Continuous Casting of Steel: Model Theory, Setup and Comparison to Physical Modelling with Liquid Metal

Abstract

Recent developments of an advanced numerical model for Continuous Casting of steel unveiled at the previous 2010 CSSCR Conference in Sapporo, Japan are presented. These include coupling of the existing multiphase, heat transfer and solidification model to argon injection for tracking bubble trajectories in the SEN, metal bulk and across the slag bed after passing through the metal surface. Hence, description of a method for adding gas injection in combination with a multiphase model for tracking metal/slag interfaces (Discrete Phase Model + Volume Of Fluid, DPM+VOF) is given.Validation is supported by tests on a revamped Continuous Casting Simulator (CCS-1) based on a low melting point alloy, which can realistically replicate the flow conditions in the caster. Metal-slag-argon flow predictions were compared to observations in the physical model showing good agreement on features such as discharging jets, rolls, standing waves and argon distribution measured through a variety of techniques such as ultrasound, electromagnetic probes and video sequences. Ultimately, the model makes possible the prediction of stable or unstable flows within the mould as a function of different argon flow-rates and bubble sizes. Application to industrial practice is an ongoing task and preliminary results are illustrated. The robustness of the model combined with direct observations in CCS-1 make possible the description of phenomena difficult to observe in the caster (e.g. argon injection and metal flow), but critical for the stability of the process and the quality of cast products.

Thermo-fluid Mathematical Modeling of Steel Slab Caster: Progress in 21st Century

“…Significant modeling efforts have been made to resolve the meniscus region by a Volume Of Fluid (VOF) approach. [44][45][46][47] The standing wave has been observed in water models and actual caster. The shape of these wave keeps fluctuating depending upon flow in the mold cavity.…”

“…Shell thinning effect due to curved nature of mold was quantified in order to prevent a break out situation. Lopez [39][40][41]44,45,93) extended the shell growth modeling in presence of multiphase and included real caster dynamics of slag infiltration with oscillation. The model revealed the initial solidification mechanism and formation of oscillation marks.…”

Large Eddy Simulation on the Two‐Phase Flow in a Water Model of Continuous Casting Strand with Gas Injection

“…The results have shown that coupling the bidirectional interactions was essential to get realistic results, especially in the presence of large gas bubbles. Lopez used the DPM Lagrangian model and VOF multiphase model to predict the multiphase (steel‐slag) flow dynamics coupled with argon injection within the CC mold . It proved that the coupling of the DPM technique to an existing CC model based on the multiphase VOF method is possible.…”

Mathematical Modeling of Multiphase Flow in Steel Continuous Casting

“…Interaction between the liquid and powder mold slag layers with the molten steel at the top surface of the mold, and the changing shape of that interface, also requires a multiphase flow analysis. [23][24][25][26][27] Stabilizing this interface to avoid excessive surface velocities, level fluctuations and profile variations is of critical importance to avoiding slag entrainment, achieving uniform slag infiltration, and avoiding surface defects, which are important to obtaining quality in the continuous-cast product. 28,29) The solidified shell is another solid phase to consider in the analysis of mold flow as the shape of the solid shell can affect the flow pattern 30) and the capture of particles such as bubbles.…”