Impact of the Electromagnetic Brake Position on the Flow Structure in a Slab Continuous Casting Mold: An Experimental Parameter Study

Schurmann, Dennis; Glavinić, Ivan; Willers, B.; Timmel, Klaus; Eckert, Sven

doi:10.1007/s11663-019-01721-x

Cited by 25 publications

(19 citation statements)

References 34 publications

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“…[6] There are already a couple of studies published that show, for the flow in the continuous casting mold, that the use of an EMBr does not exclusively result in a damping of the flow but also affects the flow structure in a way that can possibly lead to an acceleration and destabilization of the flow by large-scale fluctuations or to disturbances at the meniscus. [6][7][8][9][10] Systematic model experiments on laboratory scale in low melting point metal alloys were performed at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) to study the effect of various externally applied magnetic fields on the flow inside a mockup of a conventional CC mold. [8,[10][11][12][13] The experimental setup was equipped with suitable measurement techniques to obtain quantitative data with high temporal and spatial resolution.…”

Section: Ensuring the Quality Of Continuous Cast (Cc)mentioning

confidence: 99%

Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

Vakhrushev

Kharicha

Karimi-Sibaki

et al. 2021

Metall Mater Trans B

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A numerical study is presented that deals with the flow in the mold of a continuous slab caster under the influence of a DC magnetic field (electromagnetic brakes (EMBrs)). The arrangement and geometry investigated here is based on a series of previous experimental studies carried out at the mini-LIMMCAST facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The magnetic field models a ruler-type EMBr and is installed in the region of the ports of the submerged entry nozzle (SEN). The current article considers magnet field strengths up to 441 mT, corresponding to a Hartmann number of about 600, and takes the electrical conductivity of the solidified shell into account. The numerical model of the turbulent flow under the applied magnetic field is implemented using the open-source CFD package OpenFOAM®. Our numerical results reveal that a growing magnitude of the applied magnetic field may cause a reversal of the flow direction at the meniscus surface, which is related the formation of a “multiroll” flow pattern in the mold. This phenomenon can be explained as a classical magnetohydrodynamics (MHD) effect: (1) the closure of the induced electric current results not primarily in a braking Lorentz force inside the jet but in an acceleration in regions of previously weak velocities, which initiates the formation of an opposite vortex (OV) close to the mean jet; (2) this vortex develops in size at the expense of the main vortex until it reaches the meniscus surface, where it becomes clearly visible. We also show that an acceleration of the meniscus flow must be expected when the applied magnetic field is smaller than a critical value. This acceleration is due to the transfer of kinetic energy from smaller turbulent structures into the mean flow. A further increase in the EMBr intensity leads to the expected damping of the mean flow and, consequently, to a reduction in the size of the upper roll. These investigations show that the Lorentz force cannot be reduced to a simple damping effect; depending on the field strength, its action is found to be topologically complex.

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Section: Ensuring the Quality Of Continuous Cast (Cc)mentioning

confidence: 99%

Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

Vakhrushev

Kharicha

Karimi-Sibaki

et al. 2021

Metall Mater Trans B

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“…The exterior magnetic field remained constant. Therefore, the braking force was determined by the induced current density, as expressed by Equation (15). Induced current density lines from a nozzle jet are shown in Figure 5, in which the jet is a velocity isosurface of 0.65 m/s.…”

Section: Electromagnetic Fieldsmentioning

confidence: 99%

“…Chaudhary [14] revealed that the position of the level magnetic field had remarkable effects on fluid flow and suggested preventing a transverse magnetic field from crossing the well of the submerged entry nozzle due to the low-frequency variations monitored in the mold. Schurman et al [15] focused on the position and magnetic field strength of the single-ruler EMBr in a Mini-LIMMCAST facility. The experimental results showed that an appropriate transverse magnetic field position could reduce the slag-metal interface velocity by 50% and had the same importance as the regulation of the magnetic field strength.…”

Section: Introductionmentioning

confidence: 99%

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

Wang

Liu

2021

Metals

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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.

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“…Table 1. Physical properties of gallium-indium-tin [17]. The setup consists of a small-scale model of the mold and strand of a continuous slab caster.…”

Section: Mini-limmcast Facilitymentioning

confidence: 99%

Flow Control Based on Feature Extraction in Continuous Casting Process

Abouelazayem

Glavinić

Wondrak

et al. 2020

Sensors

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The flow structure in the mold of a continuous steel caster has a significant impact on the quality of the final product. Conventional sensors used in industry are limited to measuring single variables such as the mold level. These measurements give very indirect information about the flow structure. For this reason, designing control loops to optimize the flow is a huge challenge. A solution for this is to apply non-invasive sensors such as tomographic sensors that are able to visualize the flow structure in the opaque liquid metal and obtain information about the flow structure in the mold. In this paper, ultrasound Doppler velocimetry (UDV) is used to obtain key features of the flow. The preprocessing of the UDV data and feature extraction techniques are described in detail. The extracted flow features are used as the basis for real time feedback control. The model predictive control (MPC) technique is applied, and the results show that the controller is able to achieve optimum flow structures in the mold. The two main actuators that are used by the controller are the electromagnetic brake and the stopper rod. The experiments included in this study were obtained from a laboratory model of a continuous caster located at the Helmholtz-Zentrum Dresden Rossendorf (HZDR).

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Impact of the Electromagnetic Brake Position on the Flow Structure in a Slab Continuous Casting Mold: An Experimental Parameter Study

Cited by 25 publications

References 34 publications

Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

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

Flow Control Based on Feature Extraction in Continuous Casting Process

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