Calculation Accuracy and Efficiency of a Transient Model for Submerged Entry Nozzle Clogging

Barati, Hadi; Wu, Menghuai; Kharicha, Abdellah; Ludwig, Andreas

doi:10.1007/s11663-019-01551-x

Cited by 19 publications

(10 citation statements)

References 41 publications

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“…The objective of this study was to comprehensively study the possibility of solidification and its role in clogging of an engineering-scale SEN. A transient clogging model has already been developed for this purpose [18,19] and evaluated against a laboratory experiment (clogging simulator). [15] The model simulated the mechanism of NMI transport/deposition on the nozzle wall.…”

Section: Introductionmentioning

confidence: 99%

Role of Solidification in Submerged Entry Nozzle Clogging During Continuous Casting of Steel

Barati

Kharicha

et al. 2020

steel research int.

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Metallurgists are embroiled in a debate on the role of solidification in submerged entry nozzle (SEN) clogging during continuous casting of steel: does clogging originate from solidification, or does clogging cause the solidification? This study tries to clarify this debate. An enthalpy‐based mixture continuum model is used to simulate solidification in a clog structure. The 3D structure of the clog is reconstructed using X‐ray tomography images of an as‐clogged piece in an SEN, and is directly used in the numerical model. The flow and solidification in the open pores/channels of the clog structure are then calculated. The modeling results demonstrate that although solidification does occur deep in the clog structure as the melt flow is stopped, a gap remains between the solidification and clog fronts. This gap signifies an open‐channel clog region, and the clog structure in this region needs to be mechanically strong to withstand the impact of the melt flow; otherwise, fragmentation occurs. The study verifies that the solidification cannot occur before clogging if the molten steel has sufficient superheat and the SEN is properly preheated. A SEN made of an isolating refractory material can postpone the clogging, thereby extending its service life.

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Section: Introductionmentioning

confidence: 99%

Role of Solidification in Submerged Entry Nozzle Clogging During Continuous Casting of Steel

Barati

Kharicha

et al. 2020

steel research int.

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“…[15,16] The model was evaluated against a laboratory experiment, [17] and its accuracy and efficiency were examined for industry-scale SENs. [18] The model was also successfully used to study the role of steel solidification in SEN clogging. [19] However, the chemical reactions between the steel melt and the SEN refractory during the early stage of clogging were oversimplified.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Modeling of the Early Stage of Clogging of the SEN During Continuous Casting of Ti-ULC Steel

Barati¹,

Wu²,

Michelic

et al. 2021

Metall Mater Trans B

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The clogging of the submerged entry nozzle (SEN) during the continuous casting of steel can be divided into two stages: the “early stage,” when the initial layer of the clog covers the SEN refractory surface owing to chemical reactions, and the “late stage,” when the clog layer continues to grow because of the deposition of non-metallic inclusions (NMIs). In this paper, a mathematical formulation is proposed for the build-up of the initial oxide. The chemical reaction mechanism is based on the work of Lee and Kang (Lee et al. in ISIJ Int 58:1257–1266, 2018): a reaction among SEN refractory constituents produces CO gas, which can re-oxidize the steel melt and consequently form an oxide layer on the SEN surface. The proposed formulation was further incorporated as a sub-model in a transient clogging model, which was previously developed by the current authors to track the late stage of clogging. The thermodynamics and kinetics of CO production, depending on the local pressure and temperature, must be considered for the sub-model of early-stage clogging. Test simulations based on a section of an actual industrial SEN were conducted, and it was verified that the clogging phenomenon is related to the SEN refractory, the chemical reaction with the steel melt, the local temperature and pressure, and the transport of NMIs by the turbulent melt flow in the SEN. The model was qualitatively validated through laboratory experiments. The uncertainty of some parameters that govern the reaction kinetics and permeability of the oxide layer is discussed.

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“…Recently, an advanced model was developed based on turbulent quantities near the refractory wall [61,62] to study whether clogging or parasitic solidification dominates. This model was employed together with a solidification model to analyze which phenomenon is dominant [63,64]; using an experimental setup with melt velocities of~4-5 m/s, solidification inside the SEN was found to follow the clogging front.…”

Section: Introductionmentioning

confidence: 99%

On Modelling Parasitic Solidification Due to Heat Loss at Submerged Entry Nozzle Region of Continuous Casting Mold

Vakhrushev

Kharicha

et al. 2021

Metals

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Continuous casting (CC) is one of the most important processes of steel production; it features a high production rate and close to the net shape. The quality improvement of final CC products is an important goal of scientific research. One of the defining issues of this goal is the stability of the casting process. The clogging of submerged entry nozzles (SENs) typically results in asymmetric mold flow, uneven solidification, meniscus fluctuations, and possible slag entrapment. Analyses of retained SENs have evidenced the solidification of entrapped melt inside clog material. The experimental study of these phenomena has significant difficulties that make numerical simulation a perfect investigation tool. In the present study, verified 2D simulations were performed with an advanced multi-material model based on a newly presented single mesh approach for the liquid and solid regions. Implemented as an in-house code using the OpenFOAM finite volume method libraries, it aggregated the liquid melt flow, solidification of the steel, and heat transfer through the refractory SENs, copper mold plates, and the slag layer, including its convection. The introduced novel technique dynamically couples the momentum at the steel/slag interface without complex multi-phase interface tracking. The following scenarios were studied: (i) SEN with proper fiber insulation, (ii) partial damage of SEN insulation, and (iii) complete damage of SEN insulation. A uniform 12 mm clog layer with 45% entrapped liquid steel was additionally considered. The simulations showed that parasitic solidification occurred inside an SEN bore with partially or completely absent insulation. SEN clogging was found to promote the solidification of the entrapped melt; without SEN insulation, it could overgrow the clogged region. The jet flow was shown to be accelerated due to the combined effect of the clogging and parasitic solidification; simultaneously, the superheat transport was impaired inside the mold cavity.

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Calculation Accuracy and Efficiency of a Transient Model for Submerged Entry Nozzle Clogging

Cited by 19 publications

References 41 publications

Role of Solidification in Submerged Entry Nozzle Clogging During Continuous Casting of Steel

Role of Solidification in Submerged Entry Nozzle Clogging During Continuous Casting of Steel

Mathematical Modeling of the Early Stage of Clogging of the SEN During Continuous Casting of Ti-ULC Steel

On Modelling Parasitic Solidification Due to Heat Loss at Submerged Entry Nozzle Region of Continuous Casting Mold

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