Pressure Distribution and Flow Rate Behavior in Continuous-Casting Slide-Gate Systems: PFSG

Olia, Hamed; Yang, Hyunjin; Cho, Seong-Mook; Liang, Mingyi; Das, Lipsa; Thomas, Brian G.

doi:10.1007/s11663-022-02476-8

Cited by 8 publications

(6 citation statements)

References 25 publications

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“…First, the mean bubble size needed by the multiphase flow model was predicted using a model of pressure distribution and flow rate within a slide-gate flow delivery system, PFSG [5], to find the local pressure, and a two-stage bubble size model for gas injection into downward flowing metal [6]. The results were implemented into a Rosin-Rammler distribution, based on water model measurements, in order to estimate the bubble size distribution for the particle transport model in the steel caster [1].…”

Section: Computational Modelsmentioning

confidence: 99%

Model of multiphase flow, superheat transport, and particle capture in a steel continuous caster

Liang

Cho

Ruan

et al. 2023

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

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A model of turbulent multiphase flow, heat transfer, and particle entrapment during continuous casting of steel is presented. The model includes the top 7m of the vertical and curved strand, and considers the effects of argon gas injection and thermal buoyancy. RANS model flow results are compared with LES. Lagrangian particle transport through the Eulerian-Eulerian multiphase flow field from the k-ɛ RANS model is based on random walk and features advanced particle capture criteria, improved from previous work by including anisotropic turbulent velocity fluctuations near the walls. Particle capture via 3 mechanisms is included: capture by solidified hooks at the meniscus, entrapment between dendrites, and engulfment by surrounding large particles. The fluid flow and bubble/inclusion capture results are validated with plant measurements, including nail board dipping tests and ultrasonic tests of particle locations, and good agreement is seen. The superheat has negligible effect on flow in the mold region but causes complex flow in the lower strand by creating multiple recirculation zones due to the thermal buoyancy. With high (30 K) superheat, this leads to less penetration, and slightly fewer and shallower capture of particles. Lower (10 K) superheat may enable significant top surface freezing, leading to very large internal defect clusters. Lower superheat also leads to deeper meniscus hooks, and more surface capture. Capture bands occur near the transition from vertical to curved, where downward liquid flow velocity balances the particle terminal velocity.

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Section: Computational Modelsmentioning

confidence: 99%

Model of multiphase flow, superheat transport, and particle capture in a steel continuous caster

Liang

Cho

Ruan

et al. 2023

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

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“…Figure 1 shows a flow chart of the computational model system. First, the mean bubble size needed by the multiphase flow model was predicted using a model of pressure distribution and flow rate within a slide-gate flow delivery system (PFSG) model [53] to find the local pressure, and a two-stage bubble size model for gas injection into downward flowing metal [54]. With the predicted mean bubble size and a spread parameter from the curve fitting of a water model experiment, the bubble size distribution was obtained.…”

Section: Computational Models and Solution Proceduresmentioning

confidence: 99%

“…The mean initial bubble size was calculated by the two-stage bubble formation model, knowing the pressure at the injection point from the PFSG model [53,54].…”

Section: Initial Bubble Size Models: Pfsg and Two-stage Modelmentioning

confidence: 99%

“…The PFSG model is a one-dimensional pressure energy model used to calculate the pressure distribution and flow rate in slide-gate nozzle systems for the argon-molten-steel flow system, including argon gas expansion by solving the Bernoulli equation [53]. This model was verified with CFD simulations and validated with plant measurements and water model measurements, with errors of less than 6% [53]. With the hot molten steel pressure P h at the injection location predicted by the PFSG model, the hot argon gas flow rate Q h can be calculated by:…”

Section: Initial Bubble Size Models: Pfsg and Two-stage Modelmentioning

confidence: 99%

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Modeling of Multiphase Flow, Superheat Dissipation, Particle Transport, and Capture in a Vertical and Bending Continuous Caster

et al. 2022

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A new model of particle entrapment during continuous casting of steel is presented, which includes the effects of multiphase flow from argon gas injection and thermal buoyancy from superheat in the strand. The model simulates three different capture mechanisms, including capture by solidified hooks at the meniscus, entrapment between dendrites, and engulfment by the surrounding of large particles. The fluid flow and bubble capture results are validated with plant measurements, including nail board dipping tests and ultrasonic tests, respectively, and good agreement is seen. Results suggest that the superheat has a negligible effect on the flow in the mold region. However, higher (30 K) superheat causes a more complex flow in the lower strand by creating multiple recirculation zones due to the thermal buoyancy effects. This causes less penetration deep into the strand, which leads to fewer and shallower particle captures. Lower (10 K) superheat may enable significant top surface freezing, leading to very large internal defect clusters. Lower superheat also leads to deeper meniscus hooks, which sometimes (0.003%) capture large (1 mm) bubbles. Capture bands occur near the transition line from vertical to curved, due to the downward fluid velocity balancing the particle terminal velocity, enabling capture in the relative stagnation region beneath the longitudinal recirculation zone. These findings agree with plant observations.

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“…Parallel to these, air ingression, pressure distribution, and argon bubbling in slide-gate nozzles during continuous castings have also been investigated and reported in a few works of literature. [20][21][22][23] Although air aspiration tends to occur through slide gate and LS-CN joint present in the steel teeming circuitry and the former has been given considerable attention, little or no information has been documented in the open literature on the circumferential distribution of argon in LS-CN assembly, despite the long history of shrouded steel teeming practices under protective argon atmosphere and importance of the issue. The effectiveness of different argon delivery design to the inertization of LS-CN assembly thus has remained largely unknown.…”

Section: Introductionmentioning

confidence: 99%

A New Inert Gas Delivery Design for Improved Shielding of Ladle Shroud–Collector Nozzle (LS–CN) Assembly: Modeling, Design, and Industrial‐Scale Validations

Mukherjee

Mazumdar

2022

steel research int.

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Argon injection in ladle shrouds is customarily practiced during the teeming of liquid steel from ladle to tundish to minimize air ingression and thereby restrict atmospheric oxidation of steel melt. Despite such practices, nitrogen pickup results in the tundish, implying inadequate shielding of ladle shroud-collector nozzle (LS-CN) joint. Accordingly, the efficacy of different argon injection designs in shrouds is evaluated in the present study, and thereby, a novel argon injection arrangement, embodying a twin, tangential gas discharge system, developed as a curative step to ensure maximum inertization of the LS-CN assembly. Numerical prediction of argon flow and distribution around the LS-CN assembly is accompanied by a homogeneous, non-isothermal, two-component turbulent flow model embodied in ANSYS Fluent. These, supported adequately by water modeling results, indicated that inertization of LS-CN assembly is considerably improved with the proposed design at argon flowrates typically practiced in industries (10 Nlit min À1 ). To substantiate laboratory findings, a plant-scale investigation is carried out, wherein shrouds with a new gas delivery design are fabricated and deployed in continuous bloom casting operation in a special steel plant. Industrial trials confirm the superiority of the new design over existing ones and demonstrate a 50% reduction in nitrogen pickup, during teeming, under identical operating conditions.

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Pressure Distribution and Flow Rate Behavior in Continuous-Casting Slide-Gate Systems: PFSG

Cited by 8 publications

References 25 publications

Model of multiphase flow, superheat transport, and particle capture in a steel continuous caster

Model of multiphase flow, superheat transport, and particle capture in a steel continuous caster

Modeling of Multiphase Flow, Superheat Dissipation, Particle Transport, and Capture in a Vertical and Bending Continuous Caster

A New Inert Gas Delivery Design for Improved Shielding of Ladle Shroud–Collector Nozzle (LS–CN) Assembly: Modeling, Design, and Industrial‐Scale Validations

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