Attachment of Liquid Calcium Aluminate Inclusions on Inner Wall of Submerged Entry Nozzle during Continuous Casting of Calcium-Treated Steel

Deng, Zhiyin; Zhu, Miaoyong; Zhong, Bin; Sichen, Du

doi:10.2355/isijinternational.54.2813

Cited by 17 publications

(9 citation statements)

References 15 publications

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“…Trying to reduce the clogging, argon injection through the nozzle wall has been used and recently, it has been injected at the stopper rod tip . Some others have tried to prevent nozzle clogging by calcium injection into the melt in order to produce liquid inclusions . In contrast, only a few works have been focused on the fluid dynamic of the inclusions deposition to the refractory wall.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Modeling of Inclusions Deposition at the Upper Tundish Nozzle and the Submerged Entry Nozzle

Gutiérrez

Garcia-Hernandez

Barreto

2016

steel research int.

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Nozzle clogging is still a concern for steel makers due to the high-quality requirements and productivity in the continuous casting. The present work studies the factors involved in the inclusion deposition at the nozzle wall using numerical and analytical techniques. For this, a detailed fluid dynamic analysis inside the nozzle in a coupled tundish-mold system is undertaken. The results show that the inclusions reaching the nozzle, only 30% get deposited along its walls mainly at the upper tundish nozzle (UTN) and at the submerged entry nozzle (SEN) ports. These areas of higher deposition are identified close to a low static pressure and a high turbulent kinetic energy dissipation zones. The high-energy dissipation induces a fluctuant velocity increment; consequently, the mean flow velocity increases forcing a reduction of the static pressure in order to preserve the mechanical energy balance. This mechanical energy imbalance is identified as mechanical energy dissipation being recognized by an increment in the vorticity and quantified by an additional term into Bernoulli equation. This complex phenomenon induces zones of high turbulent flow from which the inclusions tend to move toward lower turbulence regions, explaining why the inclusions get deposited in these two typical zones promoting the deleterious clogging phenomenon.

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Section: Introductionmentioning

confidence: 99%

Mathematical Modeling of Inclusions Deposition at the Upper Tundish Nozzle and the Submerged Entry Nozzle

Gutiérrez

Garcia-Hernandez

Barreto

2016

steel research int.

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“…Other works have stressed the importance of the nozzle flow patterns since inclusion deposition has presented preferential zones at the upper tundish nozzle (UTN), just after the slide gate, close to the submerged entry nozzle (SEN) ports, and at the nozzle bottom. These zones are characterized by flow recirculation, abrupt geometry changes, and high gradients on the turbulent kinetic energy, pressure, and flow velocity [16,[30][31][32][33][34][35]. Slowing down the casting speed enhances the clogging rate online with the formation of dead zones inside the nozzle [3,16,31].…”

Section: Introductionmentioning

confidence: 99%

“…The current model was selected due to that the k-ε turbulence model has shown results describing the fluid dynamic of the continuous casting and does not require a lot of computational effort [2][3][4]9,33,35,[41][42][43].…”

mentioning

confidence: 99%

Decrease of Nozzle Clogging through Fluid Flow Control

Gutiérrez

Barreto

Garcia-Hernandez

et al. 2020

Metals

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Decreasing the clogging deposition rate of alumina inclusions in continuous casting nozzles is possible through three simultaneous measures: Flow modification, use of raw materials with low impurities contents, and smoothed internal surfaces. The control of the internal flow consists on avoiding dead regions and developing symmetric patterns. A mathematical model performed tests of the feasibility of these measures. The adherence of inclusions to the nozzle wall, using this model, employs a boundary condition based on the thickness of the sublaminar boundary instead of the conventional “trap” boundary condition. The use of the general boundary condition yields deposition rates that are unaffected by the inclusion size. The proposed boundary condition discriminates against the clogging deposition rate through the particle sizes. Plant trials complemented with water modeling, using these nozzles, proved that the present approach could considerably decrease the clogging occurrence.

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“…[8][9][10][11][12] Several of the deposited inclusions are located at typical zones of the nozzle promoting the deleterious clogging phenomenon. [13][14][15][16][17][18][19][20][21] Other authors have studied the fluidynamics inside the nozzle trying to figure out the inclusion deposition at the typical adhesion zones, finding that these are related to low pressure and high turbulence zones. [22][23][24][25][26] In contrast, many researchers have tried to establish the variables affecting the inclusion trajectory, focusing on the forces balance.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Analysis of the Dynamic Effects on the Deposition of Alumina Inclusions inside the Upper Tundish Nozzle

2016

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Nozzle clogging is still a standing problem in the continuous casting of steel since the deposition of alumina inclusions inside the Upper Tundish Nozzle (UTN) affects the productivity and the product quality. The present fundamental work studies the effects of inertial, gravitational, buoyant, pressure gradient, and Saffman forces on the deposited inclusion trajectories at the typical adhesion zone inside the UTN, using analytical and numerical techniques. For this, a mathematical model was developed considering the Navier-Stokes equations, the standard k-ε model, and the Lagrangian discrete phase model for a coupled system including the tundish, the UTN, the slide gate, the SEN, and the mould. The results show that the highest inclusion deposition rate is just below a low static pressure zone. At the low static pressure zone the pressure gradient force becomes important, attracting the inclusions to the nozzle wall, and once the inclusions leave this zone, this force does not promote a significant inclusion radial movement. In addition, at the highest deposition zone, the effects of the gravitational and buoyant forces do not promote a significant inclusion radial movement since these are aligned with the direction of the flow stream lines. In contrast, the Saffman force shows an important effect on the deposited inclusions, slowing down the inclusions in the vertical axis and increasing their radial movement.

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Attachment of Liquid Calcium Aluminate Inclusions on Inner Wall of Submerged Entry Nozzle during Continuous Casting of Calcium-Treated Steel

Cited by 17 publications

References 15 publications

Mathematical Modeling of Inclusions Deposition at the Upper Tundish Nozzle and the Submerged Entry Nozzle

Mathematical Modeling of Inclusions Deposition at the Upper Tundish Nozzle and the Submerged Entry Nozzle

Decrease of Nozzle Clogging through Fluid Flow Control

Mathematical Analysis of the Dynamic Effects on the Deposition of Alumina Inclusions inside the Upper Tundish Nozzle

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