Modeling Argon Gas Behavior in Continuous Casting of Steel

Yang, Hyunjin; Vanka, Surya Pratap; Thomas, Brian G.

doi:10.1007/s11837-018-2997-7

Cited by 20 publications

(12 citation statements)

References 31 publications

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“…This hybrid model was recently applied to bubbly pipe flow experiments, 169,170) and to a lab-scale stopper-rod system using liquid Galinstan and argon gas. 21,171,172) The gas volume fraction distributions, flow pattern and bubble size distributions all compare well with the measurements.…”

Section: Eedpm Modelsupporting

confidence: 57%

Mathematical Modeling of Multiphase Flow in Steel Continuous Casting

2019

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This paper reviews multiphase flow models for continuous casting of steel from classical models to recent methods. These multiphase flow models are classified into six groups in this paper: quasi-multiphase models, multi-fluid models, moving grid methods, interface tracking methods, particle based models/ methods and hybrid models. For each model, the governing equations are summarized and the inherent advantages and disadvantages are discussed. Example applications of each model are presented from previous literature, illustrating typical results and accuracy that can be obtained. The objective of this paper is to guide readers to choose an appropriate multiphase flow model for their application. Argon gas bubble effects on the flow pattern can be modeled with simple mixture models, Eulerian-Eulerian models, Multiple size group models which also track bubble size distributions, and Discrete-Phase Models (DPM). Gas pockets and slug flow, which can occur inside the nozzle are more complex, and hybrid models which combine different models together, such as Eulerian-Eulerian, level-set, Volume of Fluid (VOF), and DPM, appear promising. The shape of the slag/steel interfacial profile, level fluctuations, and slag entrainment can be modeled with free surface methods, such as moving grid, VOF, or other interface tracking methods. Particle transport and entrapment, including inclusions and gas bubbles can be added via DPM models and also require a capture criterion model. Solidification and meniscus phenomena require flow models coupled with heat transfer and solidification.

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Section: Eedpm Modelsupporting

confidence: 57%

Mathematical Modeling of Multiphase Flow in Steel Continuous Casting

2019

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“…Many water model experiments have been conducted to investigate the bubble behaviors in the mold [5][6][7][8][9]. Mathematical simulation is another choice, which was extensively adopted [10][11][12][13][14]. However, there are still challenges in the numerical simulation due to the complexity and lack of reliable theory of the bubble behaviors.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Effect of Initial Bubble Size on Captured Bubble Distribution in Steel Continuous Casting Using Euler-Lagrange Approach Considering Bubble Coalescence and Breakup

Yang

Luo

Zhao

et al. 2020

Metals

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A mathematic model considering the bubble coalescence and breakup using the Euler-Lagrange approach has been developed to study the effect of the initial bubble size on the distribution of bubbles captured by the solidification shell. A hard sphere model was applied for dealing with the bubble collision. Advanced bubble coalescence and breakup models suitable for the continuous casting system and an advanced bubble captured criteria have been identified established with the help of user-defined functions of FLUENT. The predictions of bubble behavior and captured bubble distribution agree with the water model and plant measurements well respectively. The results show that the number of small bubbles captured by solidification shell is much higher than that of large bubbles. What is more, the number of captured bubbles at the sidewalls decreases with the distance from the meniscus. For the case of large gas flow rate (gas flow fraction of 8.2%), the initial size of bubbles has little effect on bubble captured distribution under various casting speeds. When the gas flow rate is small (gas flow fraction of 4.1%), the number density of captured bubbles increases as the initial bubble size increases, and the effect of initial bubbles size on captured bubble number density is amplified when the casting speed decreases. The average captured bubble diameter is about 0.12–0.14 mm. Additionally, for all cases, the initial bubble size hardly affects the average size of captured bubbles.

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“…Several modeling efforts have been undertaken to understand the mechanism of throughput and the overall pressure distribution of continuous casting systems using computational flow models [3,8] or the Bernoulli energy-balance approach [1,4,23]. They have revealed that the inter-related effects of slide-gate opening or stopper position, throughput, tundish level, argon gas injection and nozzle geometric parameters such as the nozzle diameter are important to the pressure distribution, but more study is needed.…”

Section: Previous Modelsmentioning

confidence: 99%

“…Recirculation zones generated by flow separation in the nozzle facilitate the deposition of oxides by offering deposit sites at the edge of the zones where velocity is lowest [7]. Recirculation zones typically form just below the slide-gate, near the aperture between stopper and nozzle wall, and at the top of the port outlet [8].…”

Section: Introductionmentioning

confidence: 99%

“…Argon injection may also lead to increased pressure inside the nozzle by causing the slide-gate to open further for a given molten steel throughput [3]. However, a previous model study [3] showed that the minimum argon gas flow rate needed to avoid negative pressure and aspiration in the SEN is typically very large, and excessive argon flow rates can be harmful [1,8,[18][19][20]. Several patents have been proposed [21,22] to apply a sealed vacuum chamber around the slide-gate to lower the external pressure.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling Air Aspiration in Steel Continuous Casting Slide-Gate Nozzles

Yang

Olia

Thomas

2021

Metals

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Air aspiration is an important cause of nozzle clogging and inclusions in final products of continuous casting of steel due to the presence of metal oxides (such as alumina) which occur through the reoxidation of molten steel. This problem is most likely to occur when the flow control system (slide-gate or stopper rod) causes the pressure inside the nozzle to drop below atmospheric pressure, drawing gas into the system through possible cracks or gaps in the refractory walls. In this work, a 1-D pressure-energy model of the complete metal delivery system from the tundish to the mold is developed to predict the pressure distribution and throughput under dynamic operating conditions and varying clogging conditions. The energy balance approach includes pressure losses in the slide-gate, wall friction, and nozzle geometry variations, including the effects of multiphase flow due to argon gas injection. The model also predicts air aspiration, oxide inclusion formation, and the time for clogging shutdown. The predicted pressure distribution is verified with a three-dimensional numerical simulation of multiphase turbulent flow, and is validated with plant measurements. Parametric studies with different submerged entry nozzle (SEN) designs revealed that a smaller SEN diameter may lessen negative pressure by redistributing the pressure loss from the slide-gate to the entire nozzle through increased friction losses. Under negative pressure, a submillimeter-thin gap was shown to cause considerable air aspiration. Clogging shutdown times were evaluated for several scenarios under static and dynamic operating conditions.

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Modeling Argon Gas Behavior in Continuous Casting of Steel

Cited by 20 publications

References 31 publications

Mathematical Modeling of Multiphase Flow in Steel Continuous Casting

Mathematical Modeling of Multiphase Flow in Steel Continuous Casting

Numerical Analysis of Effect of Initial Bubble Size on Captured Bubble Distribution in Steel Continuous Casting Using Euler-Lagrange Approach Considering Bubble Coalescence and Breakup

Modeling Air Aspiration in Steel Continuous Casting Slide-Gate Nozzles

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