Fluid Flow Behavior in Submerged Entry Nozzle of Continuous Casting

Kato, Toru; Hara, Masashi; Muto, Akifumi; Hiraki, Sei; Kawamoto, Masayuki

doi:10.2355/isijinternational.47.840

Cited by 12 publications

(7 citation statements)

References 6 publications

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“…Three types of pressure loss are considered in this 1-D model: wall friction loss, minor loss, and pressure loss due to argon gas. For the wall friction loss P L f (Equations (19), (20), (22), (23) and (25), the Darcy-Weisbach equation is applied as follows:…”

Section: Pressure Loss Calculationmentioning

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%

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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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Section: Pressure Loss Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling Air Aspiration in Steel Continuous Casting Slide-Gate Nozzles

Yang

Olia

Thomas

2021

Metals

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“…[41][42][43] Also, a few valuable studies have used low melting point alloy-argon gas system experiments to reproduce a closer situation to real continuous casting. X-ray 4,44,45) or a transparent silica glass nozzle 46) have been used to investigate argon bubble behavior in opaque liquid metal flows.…”

Section: Introductionmentioning

confidence: 99%

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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“…In the continuous steel casting process, argon, as a gas neutral to liquid steel, is used as a protective gas or medium developing the pattern of liquid steel and non‐metallic inclusions motion . The use of argon at mold submerged entry nozzles or tundish stopper rods reduces the possibility of air penetrating through the nozzle system's leaks and mitigates the process of non‐metallic inclusion deposition on the nozzle refractory lining.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Physical Modeling of Liquid Steel Flow Structure for One Strand Tundish with Modern System of Argon Injection

Cwudziński

2017

steel research int.

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In the continuous steel casting process, argon, as a gas neutral to liquid steel, is used as a protective gas or medium developing the pattern of liquid steel and non-metallic inclusions motion. With the appropriate argon flow rate, the hydrodynamic structure of liquid steel motion can be effectively modified in the tundish. The facility under investigation is a single-nozzle slab tundish. Two unique argon injection barrier have been designed, whose purpose is to stimulate the motion of liquid steel within the working space of the tundish. Computer simulations of the liquid steel flow and argon behavior were done using the Ansys-Fluent computer program. For the validation of the numerical model and verification of the correctness of the computer simulation results, a glass water model was used. It has been found that the use of the gas-permeable barrier with two porous plugs in the tundish effectively influences the pattern of liquid steel flow.

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Fluid Flow Behavior in Submerged Entry Nozzle of Continuous Casting

Cited by 12 publications

References 6 publications

Modeling Air Aspiration in Steel Continuous Casting Slide-Gate Nozzles

Modeling Air Aspiration in Steel Continuous Casting Slide-Gate Nozzles

Mathematical Modeling of Multiphase Flow in Steel Continuous Casting

Numerical and Physical Modeling of Liquid Steel Flow Structure for One Strand Tundish with Modern System of Argon Injection

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