Instability and Periodicity of Asymmetrical Flow in a Funnel Thin Slab Continuous Casting Mold

Liu, Zhongqiu; Li, Baokuan; Tsukihashi, Fumitaka

doi:10.2355/isijinternational.55.805

Cited by 23 publications

(11 citation statements)

References 24 publications

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“…In literature, various SEN models have been proposed to satisfy the demand for high-quality steel. For example, based on thin slab technology, the angle of the SEN exit ports could also be directed upward to avoid fluctuations in the liquidfree surface [7,19]. Additionally, a larger number of exit ports have been observed to improve the steel distribution to the mold [7].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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This work describes a visualization technique that allows to register and analyze flow inside a Submerged Entry Nozzle (SEN) model. The internal flow has a swirling pattern that produces characteristic flow conditions that can be used in efficiently supplying liquid steel from the tundish to the mold in the continuous casting process. The visualization method is a first step in analyzing the characteristics of the internal flow and hence in designing new SENs. A LED light source is employed to illuminate the SEN which reduces the reflections in the images. To enhance visualizations and measurements, a transparent cell consisting of a cubic volume with reduced dimensions was used to capture images from the high-speed camera and to record the flow pattern within the SEN. The SEN model consists of a vertical, constant diameter tube with two rounded exit ports located at the bottom with a downward angle of 15° each. The working fluid is water and reaches Re=10,000 within the cell. We also use the laser illuminated Particle Imaging Velocimetry (PIV) to calculate the velocity of fluid within the SEN and close to the exit ports. We confirm previously reported formation of three vortexes that interact with each other altering the swirl motion of the exit flow. Experimental results were compared with numerical simulations. The comparisons contribute to the validation of findings of Computational Fluid Dynamics (CFD) and Smoothed-Particle Hydrodynamics (SPH) results. Qualitative and quantitative similarities were found. Both physical and numerical results display a high turbulent flow behavior at the lower zone of the SEN. Experimental and numerical methods may be used together as a development method to measure and evaluate the characteristics of the flow behavior inside and outside the SEN model in order to design a better SEN to increase the quality of the steel slab.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…Many researchers have shown that inclusion distribution is largely affected by the flow field. Among these studies, the periodical biased flow is identified and characterized by water model, and is used to interpret the asymmetry distribution of inclusions in slab. However, the reason for the special distribution found in Figure , is still unknown.…”

Section: Numerical Results For Inclusion Distributionmentioning

confidence: 99%

Detection and Numerical Simulation of Non‐Metallic Inclusions in Continuous Casting Slab

Liu

et al. 2019

steel research int.

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A high-efficiency fast-detection platform (FDP) is set up to detect the spacial distribution of non-metallic inclusions in slab. The spacial distribution of inclusion in the slab is asymmetrical and non-uniform. In the vertical part of the caster, more inclusions are found in the loose side; while in the bending part, more inclusions are found in the fixed side. Two main sources of inclusions are revealed through SEM þ EDS method: slag entrapment and oxidation of molten steel. The reason for these large inclusions is because of the high super heat and excessive rate of water cooling, since the micro structure is proven to be Widmanstatten. Then, a large eddy simulation (LES) model coupled with solidification is developed to study the inclusion transport and entrapment in the mold. Results show that the velocity near the fixed side is larger than that in the loose side, leading to the fact that more inclusions are removed from the top surface at the fixed side. Smaller inclusions are easier taken deep into the bending part of the caster, and are dragged by the curvature of fixed side, leading to the fact that inclusions in the fixed side are more than that in the loose side.

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“…The thin slab casting process is an example of the technological improvements in steel production; nevertheless, due to its high casting velocities and the small slab thickness, the liquid steel inside produces complex turbulent phenomena adversely affecting the final product quality. On this line, many researchers have focused their efforts on studying these turbulent phenomena, searching for a deeper understanding of how to control or eradicate them [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Some of the most commonly observed phenomena are asymmetries and oscillations of the flow patterns inside the mold, identified through mathematical simulations [2,4,5,7,10,11,[14][15][16][17][18][19] or by physical modeling [6,[9][10][11][12][13][15][16][17], formation of strong recirculation at each SEN side [7][8][9][10][11]…”

Section: Introductionmentioning

confidence: 99%

“…Some of the most commonly observed phenomena are asymmetries and oscillations of the flow patterns inside the mold, identified through mathematical simulations [2,4,5,7,10,11,[14][15][16][17][18][19] or by physical modeling [6,[9][10][11][12][13][15][16][17], formation of strong recirculation at each SEN side [7][8][9][10][11][12][13][14][15][16][17][18][19], meniscus fluctuations [8][9][10][11][12][13][14][15][16][17]19], meniscus vortex formation [10][11][12][17][18]…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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The turbulent phenomena occurring in the thin slab mold affect the final product quality. Therefore, it is essential to carry out studies to understand and control their occurrence. Current research aims to study the electromagnetic brake (EMBr) effects on the flow patterns in a funnel thin slab mold. The objective is to prevent the detrimental phenomenon known as dynamic distortions (DD) of the flow, applying the EMBr in the typical horizontal position (H-EMBr) and a new vertical position close to the narrow faces (V-EMBr). The fluid dynamics are simulated using the Reynolds stress model (RSM), the Volume of Fluid (VOF) model and the Maxwell equations in their magnetohydrodynamics (MHD) simplification. The results show that the H-EMBr effectively counteracts the DD phenomenon by reducing the submerged entry nozzle (SEN) ports' mass flow rate differences. The EMBr reduces the highest meniscus fluctuations from −10 to ±3 mm with a field intensity of 0.1T and almost 0 mm for higher field intensities. In contrast, the V-EMBr configuration does not reduce or control at all the DD phenomenon, even though eliminating the upper roll flows does not diminish the meniscus fluctuation amplitudes and induces new small roll flows close to the SEN's wall.

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Instability and Periodicity of Asymmetrical Flow in a Funnel Thin Slab Continuous Casting Mold

Cited by 23 publications

References 24 publications

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

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

Detection and Numerical Simulation of Non‐Metallic Inclusions in Continuous Casting Slab

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

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