Large Eddy Simulation of Electromagnetic Three‐Phase Flow in a Round Bloom Considering Solidified Shell

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Electromagnetic fields have emerged as powerful tools for addressing current problems in thin slab continuous casting processes in the iron and steel industry. Substantial studies have been undertaken on the fundamental effects of electromagnetic brakes (EMBr) and strand electromagnetic stirring (SEMS). However, little attention has been focused on melt flow and solidification in a thin slab continuous caster with the simultaneous application of an EMBr and SEMS. The present study aimed to predict transient fields in the caster using a large eddy simulation and an enthalpy-porosity method. The electric potential method was applied in the braking process, and the conductivity change with solidification was considered. The suppressive effect on the intensity of the nozzle jet, the balance effect on the mold flow, and a dispersion effect could be observed. The dispersion effect was a novel finding and was beneficial to a flatter nozzle jet. In contrast, SEMS caused a highly turbulent flow in the strand. A large vortex could be observed in the casting direction. The solidified shell became more uniform, and the solidification rate became obviously slower. These findings supported the view that a high-quality thin slab can be produced by the application of an EMBr and SEMS.

Section: Electromagnetic Stirring Forcementioning

confidence: 99%

Combined Effects of EMBr and SEMS on Melt Flow and Solidification in a Thin Slab Continuous Caster

Wang

Liu

2021

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“…Here, the term ρ m is mixture density, P is the static pressure, F is the particle force acted on steel, F T is the surface tension at the interface [21], and the µ e f f ect = µ m + µ t is the effective viscosity of mixture phase. The term µ m is the molecular viscosity of the mixture phase and µ t is the turbulent viscosity of mixture phase.…”

Section: Les Modelmentioning

confidence: 99%

“…Many researchers have investigated the fluctuations of the slag-metal interface in the mold [17,20,21]. However, the interface fluctuations are monitored only on some limited points.…”

Section: Turbulent Behavior Of Two Interfaces In the Moldmentioning

confidence: 99%

Large Eddy Simulation of Multi-Phase Flow and Slag Entrapment in a Continuous Casting Mold

Liu

et al. 2018

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A transient, three-dimensional mathematical model has been developed to study the slag entrapment in a continuous casting mold. The unsteady turbulent flow is computed using the large eddy simulation (LES). The sub-grid scale structure is modeled by the Smagorinsky-Lilly model. The movements of discrete bubbles, as well as three continuous phases (air-slag-steel), are described by solving the coupled discrete particle model and volume of fraction (DPM+VOF) approach. The bubble transport inside different phases (steel and slag) and the escape near the air-slag interface are well studied. Good agreement is obtained by comparing with the plant observation of the slag eyes on the top surface of the mold. Three main mechanisms of slag entrapment are identified; vortex formation, shear-layer instability, and meniscus fluctuation. Four stages are observed for a slag entrapment: deformation, necking, breaking, and dragging in the mold. The model is helpful for understanding the formation of slag entrapment during continuous casting.

“…The flow pattern in the lower recirculation zone is asymmetrical and changes over a certain period; however, the periodical flow in these studies was found in slabs with a two-port submerged entry nozzle (SEN). Until now, there have been few reports about asymmetrical flows injected from a straight nozzle, except for some works by Willers [22] and Li [23]. Based on the experiment of Willers [22], there exists a secondary motion in the upper part of the mold, and this causes a strong deformation of the free surface during and after MEMS.…”

Section: Introductionmentioning

confidence: 99%

Effect of Electromagnetic Frequency on the Flow Behavior in Mold during Bloom Casting

Wang

et al. 2021

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Considering solidification, a large eddy simulation (LES) model of two-phase flow was established to simulate the thermal–magnetic flow coupled fields inside a jumbo bloom. The magnetic field was calculated based on Maxwell’s equations, constitutive equations, and Ohm’s law. An enthalpy–porosity technique was used to model the solidification of the steel. The movement of the free surface was described by the volume of fluid (VOF) approach. With the effect of electromagnetic stirring (MEMS), the vortices in the bloom tended to be strip-like; large vortices mostly appeared in the injection zone, while small ones were found near the surface of the bloom. It is newly found that even though the submerged entry nozzle (SEN) is asymmetrical about the bloom, a biased flow can also be found under the effect of MEMS. The reason for this phenomenon is because the magnetic force is asymmetrical and transient. A high frequency will reduce the period of biased flow; however, the frequency should not be too high because it could also intensify meniscus fluctuations and thus entrap slag droplets in the mold. The velocity near the solidification front can also be increased with a higher frequency.