Water model study of horizontal molten steel-Ar two-phase jet in a continuous casting mold

Iguchi, Manabu; Kasai, Norifumi

doi:10.1007/s11663-000-0151-7

Cited by 27 publications

(10 citation statements)

References 14 publications

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“…[19,[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] The first study was carried out by Afanaseva et al [31] for a straight bore nozzle system. Heaslip et al extensively studied the fluid flow in SENs under stopper-rod control and slide-gate control.…”

Section: A Similarity Criterion Of Water Model Experimentsmentioning

confidence: 99%

Investigation of Fluid Flow and Steel Cleanliness in the Continuous Casting Strand

Zhang

Yang

Cai

et al. 2007

Metall Mater Trans B

168

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Fluid flow in the mold region of the continuous slab caster at Panzhihua Steel is investigated with 0.6-scale water model experiments, industrial measurements, and numerical simulations. In the water model, multiphase fluid flow in the submerged entry nozzle (SEN) and the mold with gas injection is investigated. Top surface level fluctuations, pressure at the jet impingement point, and the flow pattern in the mold are measured with changing submergence depth, SEN geometry, mold width, water flow rate, and argon gas flow rate. In the industrial investigation, the top surface shape and slag thickness are measured, and steel cleanliness including inclusions and the total oxygen (TO) content are quantified and analyzed, comparing the old and new nozzle designs. Three kinds of fluid flow pattern are observed in the SEN: ''bubbly flow,'' ''annular flow,'' and an intermediate critical flow structure. The annular flow structure induces detrimental asymmetrical flow and worse level fluctuations in the mold. The SEN flow structure depends on the liquid flow rate, the gas flow rate, and the liquid height in the tundish. The gas flow rate should be decreased at low casting speed in order to maintain stable bubbly flow, which produces desirable symmetrical flow. Two main flow patterns are observed in the mold: single roll and double roll. The single-roll flow pattern is generated by large gas injection, small SEN submergence depth, and low casting speed. To maintain a stable double-roll flow pattern, which is often optimal, the argon should be kept safely below a critical level. The chosen optimal nozzle had 45-mm inner bore diameter, downward 15 deg port angle, 2.27 port-to-bore area ratio, and a recessed bottom. The pointed-bottom SEN generates smaller level fluctuations at the meniscus, larger impingement pressure, deeper impingement, and more inclusion entrapment in the strand than the recess-bottom SEN. Mass balances of inclusions in the steel slag from slag and slab measurements show that around 20 pct of the alumina inclusions are removed from the steel into the mold slag. However, entrainment of the mold slag itself is a critical problem. Inclusions in the steel slabs increase twofold during ladle changes and tenfold during the start and end of a sequence. All of the findings in the current study are important for controlling slag entrainment.

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Section: A Similarity Criterion Of Water Model Experimentsmentioning

confidence: 99%

Investigation of Fluid Flow and Steel Cleanliness in the Continuous Casting Strand

Zhang

Yang

Cai

et al. 2007

Metall Mater Trans B

168

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“…31) It is critically important to validate models with experimental measurement. Several methods have been employed to measure the fluid flow velocity vectors in continuous casting mold system, including LDV (Laser Doppler Velocimetry) for mold 16,57) and for SEN nozzle 58,59) ), PIV (Particle Image Velocimetry), 19,25,60,61) hot wire anemometry 62) ; and propeller flow meters. [63][64][65] Figure 3 compares the instantaneous flow patterns predicted using physical and mathematical models for a typical double-roll flow pattern condition.…”

Section: Flow In the Moldmentioning

confidence: 99%

“…Extensive past work has employed physical water models to successfully investigate fluid flow phenomena in the mold region of the continuous casting process. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] The first study was carried out by Afanaseva et al 1) for a straight bore nozzle system. Heaslip et al extensively studied fluid flow in submerged entry nozzles under stopper-rod control and slide-gate control.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Modeling of Iron and Steel Making Processes. Mathematical Modeling of Fluid Flow in Continuous Casting.

2001

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Fluid flow is very important to quality in the continuous casting of steel. With the high cost of empirical investigation and the increasing power of computer hardware and software, mathematical modeling is becoming an important tool to understand fluid flow phenomena. This paper reviews recent developments in modeling phenomena related to fluid flow in the continuous casting mold region, and the resulting implications for improving the process. These phenomena include turbulent flow in the nozzle and mold, the transport of bubbles and inclusion particles, multi-phase flow phenomena, the effect of electromagnetic forces, heat transfer, interfacial phenomena and interactions between the steel surface and the slag layers, the transport of solute elements and segregation. The work summarized in this paper can help to provide direction for further modeling investigation of the continuous casting mold, and to improve understanding of this important process.KEY WORDS: mathematical modeling; computational simulation; review; continuous casting; nozzles; molds; multiphase; turbulent; fluid flow; electromagnetic; coupled solidification; inclusion entrapment; segregation.steel. This paper will review recent developments in modeling each of the phenomena above, which are related to fluid flow in the continuous casting mold, and the resulting implications for improving the continuous casting process. Fluid Flow ModelingA typical three dimensional fluid flow model solves the continuity equation and Navier Stokes equations for incompressible Newtonian fluids, which are based on conserving mass (one equation) and momentum (three equations) at every point in a computational domain. 17,18) The solution of these equations, given elsewhere in this issue, 19) yields the pressure and velocity components at every point in the domain. At the high flow rates involved in this process, these models must incorporate turbulent fluid flow. Many different turbulence models have been employed by different researchers for fluid flow in continuous casting, such as effective viscosity models 20,21) (for the cylindrical mold and straight nozzle), one equation turbulence models (turbulent energy plus a given length-scale), 22) two-equation turbulence models such as the K-e Model, 19,23) LES (Large Eddy Simulation), [24][25][26][27][28] possibly with a SGS (sub-grid scale) model, 29,30) and DNS (Direction Numerical Simulation). 19)Among these models, direct numerical simulation is the simplest yet most computationally-demanding method. DNS uses a fine enough grid (mesh), to capture all of the turbulent eddies and their motion with time. To achieve more computationally-efficient results, turbulence is usually modeled on a courser grid using a time-averaged approximation, such as the popular K-e model, 23) which averages out the effect of turbulence using an increased effective viscosity field, m eff . This approach requires solving two additional partial differential equations for the transport of turbulent kinetic energy and its dissipation rate.19...

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“…The injected gas bubbles have a distinct influence on the flow pattern and may trigger instabilities in the mold, for instance, observations made on real casters showed correlations between argon gas pressure variations in the submerged entry nozzle (SEN) and mold meniscus perturbations. [1] Gas-liquid flows within the SEN and the mold have been addressed by many studies, whereas previous contributions to a better understanding of complex two-phase flows in metallurgical processes have been obtained by a combination of numerical modeling and up to 1:1-scale water models [2][3][4][5][6][7][8][9][10][11][12][13][14][15] and experimental trials at real casting machines. [1,16] Bai and Thomas [4] used 3-D numerical simulations and a water model to investigate the effect of argon bubbles on the turbulent steel flow in a sliding gate configuration.…”

Section: Introductionmentioning

confidence: 99%

Visualization of Liquid Metal Two-phase Flows in a Physical Model of the Continuous Casting Process of Steel

Timmel

Shevchenko

Röder

et al. 2014

Metall Mater Trans B

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We present an experimental study concerned with investigations of the two-phase flow in a mock-up of the continuous casting process of steel. A specific experimental facility was designed and constructed at HZDR for visualizing liquid metal two-phase flows in the mold and the submerged entry nozzle (SEN) by means of X-ray radioscopy. This setup operates with the low melting, eutectic alloy GaInSn as model liquid. The argon gas is injected through the tip of the stopper rod into the liquid metal flow. The system operates continuously under isothermal conditions. First results will be presented here revealing complex flow structures in the SEN widely differing from a homogeneously dispersed bubbly flow. The patterns are mainly dominated by large bubbles and large-area detachments of the liquid metal flow from the inner nozzle wall. Various flow regimes can be distinguished depending on the ratio between the liquid and the gas flow rate. Smaller gas bubbles are produced by strong shear flows near the nozzle ports. The small bubbles are entrained by the submerged jet and mainly entrapped by the lower circulation roll in the mold. Larger bubbles develop by coalescence and ascend toward the free surface.

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Water model study of horizontal molten steel-Ar two-phase jet in a continuous casting mold

Cited by 27 publications

References 14 publications

Investigation of Fluid Flow and Steel Cleanliness in the Continuous Casting Strand

Investigation of Fluid Flow and Steel Cleanliness in the Continuous Casting Strand

Mathematical Modeling of Iron and Steel Making Processes. Mathematical Modeling of Fluid Flow in Continuous Casting.

Visualization of Liquid Metal Two-phase Flows in a Physical Model of the Continuous Casting Process of Steel

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