Modeling Study of EMBr Effects on the Detrimental Dynamic Distortion Phenomenon in a Funnel Thin Slab Mold

Garcia-Hernandez, Saul; Gonzalez-Guzman, Carlos Humberto; Dávila, Rodolfo Morales; Barreto, José de Jesús; Gutiérrez, E.; Calderon-Ramos, Ismael

doi:10.3390/cryst10110958

Cited by 11 publications

(8 citation statements)

References 45 publications

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“…Garcia-Hernandez et al observed perturbations of the meniscus level in thin slab castings due to periodic flow alterations and refer to this turbulent behavior of the flow under the term dynamic distortions (DDs). [21] The authors investigated whether and how the horizontal and vertical EMBrs can be applied to prevent the occurrence of DDs at the meniscus. While there seems to be some success in the case of the horizontal EMBr, the authors surprisingly failed to show a way to prevent or control the DD phenomenon using the vertical EMBr.…”

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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“…However, a series of recent studies has revealed the details of its complex topology, which leads to the entrainment of the quiescent melt into the formation of the reverse zones near the jets and in the upper region of the CC mold [8][9][10]. The flow pattern in the mold, the superheat distribution and the melt solidification are significantly altered under the EMBr during the continuous casting (CC) process [11][12][13][14][15][16][17]. The influence of the applied magnetic field on the asymmetric flow inside a TSC mold due to the partial SEN blockage was recently presented by the authors including effects on the solidification profiles [18].…”

Section: Introductionmentioning

confidence: 99%

Influence of the adjustable EMBr on the asymmetric flow in a thin slab caster with a misaligned SEN

Vakhrushev

Karimi-Sibaki

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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The thin slab casting (TSC) of steel is a type of the continuous casting (CC) with a narrow funnel-shaped mold, characterized by the rapid solidification and fast production rates. A highly turbulent flow impacts on a growing solid shell due to the constant feeding of the fresh hot melt. That strongly affects the solidification profiles and final quality of the TSC slabs. The presented work numerically investigates the solidification inside the TSC mold with the asymmetric flow pattern caused by the misalignment (tilting) of the submerged entry nozzle (SEN). These effects were considered with and without the applied electromagnetic brake (EMBr). The influence of the adjustable EMBr on the asymmetric flow and solidification profiles including turbulent and magnetohydrodynamic (MHD) effects were studied. During consistent series of simulations, the EMBr was varied between the magnetic poles and the time-averaged velocity and temperature fields were collected. The results showed that symmetric EMBr of a local type could partially improve the asymmetry. An optimal braking scenario was found for the casing speed of 5.5 m/min and maximum EMBr value of 180 mT. The solidification and MHD models including turbulence were developed using OpenFOAM®.

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“…These include the effects of liquid steel mass reduction due to solidification [8], shell formation, model bottom, and electromagnetic brake [9,10], and its effect on the level of fluctuation heights in the mold [11,12]. In this case, electromagnetic fields have emerged as powerful tools for addressing current problems in thin-slab continuous casting processes in the iron and steel industry [13]. In particular, the electromagnetic brake adopted a new magnet type specially designed for the thin-slab casting funnel-shaped mold [14].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, authors like Wang et al [15] studied predicting transient fields in the caster using a large eddy simulation and an enthalpy-porosity method; such a method helps predict the solidification shell in addition to increasing the possibility of washing the solidified steel crust [16] and possible wire breakage [17]. Also, there are other consequences to consider: slag trapping toward the sinus of liquid metal [18,19], slag droplets into steel volume [20], the movement of inclusions [13], and the possible reoxidation of the liquid steel due to the opening of the slag [21,22], as has been shown through numerical simulation techniques using colorimetry and PIV [23].…”

Section: Introductionmentioning

confidence: 99%

Design and Optimization of the Internal Geometry of a Nozzle for a Thin-Slab Continuous Casting Mold

Chiwo,

Susunaga-Notario,

Betancourt-Cantera

et al. 2023

Designs

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Understanding the phenomena that cause jet oscillations inside funnel-type thin-slab molds is essential for ensuring continuous liquid steel delivery, improving flow pattern control, and increasing plant productivity and the quality of the final product. This research aims to study the effect of the nozzle’s internal design on the fluid dynamics of the nozzle-mold system, focusing on suppressing vorticity generation below the nozzle’s tip. The optimized design of the nozzle forms the basis of the results obtained through numerical simulation. Mathematical modeling involves fundamental equations, the Reynolds Stress Model for turbulence, and the Multiphase Volume of Fluid model. The governing equations are discretized and solved using the implicit iterative-segregated method implemented in FLUENT®. The main results demonstrate the possibility of controlling jet oscillations even at high casting speeds and deep dives. The proposed modification in the internal geometry of the nozzle is considered capable of modifying the flow pattern inside the mold. The geometric changes correspond with 106% more elongation than the original nozzle; the change is considered 17% of an inverted trapezoidal shape. Furthermore, there was a 2.5 mm increase in the lower part of both ports to compensate for the inverted trapezoidal shape. The newly designed SEN successfully eliminated the issue of jet oscillations inside the mold by effectively preventing the intertwining of the flow. This improvement is a significant upgrade over the original design. At the microscale, a delicate force balance occurs at the tip of the nozzle’s internal bifurcation, which is influenced by fluctuating speeds and ferrostatic pressure. Disrupting this force balance leads to increased oscillations, causing variations in the mass flow rate from one port to another. Consequently, the proposed nozzle optimization design effectively controls microscale fluctuations above this zone in conjunction with changes in flow speed, jet oscillation, and metal–slag interface instability.

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Modeling Study of EMBr Effects on the Detrimental Dynamic Distortion Phenomenon in a Funnel Thin Slab Mold

Cited by 11 publications

References 45 publications

Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

Influence of the adjustable EMBr on the asymmetric flow in a thin slab caster with a misaligned SEN

Design and Optimization of the Internal Geometry of a Nozzle for a Thin-Slab Continuous Casting Mold

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