Multiphase Modeling of Bottom-Stirred Ladle for Prediction of Slag–Steel Interface and Estimation of Desulfurization Behavior

Singh, Umesh; Anapagaddi, Ravikiran; Mangal, Saurabh; Padmanabhan, K. A.; Singh, Amarendra K.

doi:10.1007/s11663-016-0620-2

Cited by 41 publications

(37 citation statements)

References 36 publications

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“…The multiphase flow in a gas-stirred ladle was simulated by the volume of fluid (VOF) model, and the control equations were described as follows: 5,8,[31][32][33][34] (1) Continuity equation…”

Section: Mathematical Modeling 221 Control Equationmentioning

confidence: 99%

“…Moreover, higher degree of turbulence in this case leads to slag entrapment in steel and enhances the formation of exogenous inclusions. 5) Thus, it is of great significance to determine proper argon stirring flowrate. Moreover, for high-capacity ladles used in many steel factories of China, two porous plugs are usually utilized, and their positions and relative angle have effect on the homogenization of molten steel.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, for high-capacity ladles used in many steel factories of China, two porous plugs are usually utilized, and their positions and relative angle have effect on the homogenization of molten steel. 1,6) For the function of argon gas in ladle refining, many studies were performed in the earlier years through water model 1,2,4,6) and mathematical simulation 5,[7][8][9] from different aspects such as (a) gas injection and transport, [10][11][12][13] (b) the effect of top slag layer, [14][15][16][17][18][19] (c) stirring and mixing. [20][21][22][23][24][25][26][27][28] In 1975, Nakanishi et al 10) investigated the correlation between gas mixing efficiency and mass transfer in a model ladle and explained this correlation with turbulence theory.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Gas Blown Modes on Mixing Phenomena in a Bottom Stirring Ladle with Dual Plugs

Tang

Guo

et al. 2016

ISIJ International

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Gas stirring plays a significant role in steelmaking process. The stirring effect is often assessed by the mixing time. In the past, the effects of many factors such as the number and position and relative angle of porous plugs in a ladle, as well as gas flowrate on the mixing time have been studied and some beneficial results used in industrial practice. However, for a ladle with dual plugs, the researches on gas flowrate basically focused on the blowing mode with the same gas flowrates for every plug (Mode-S), while the mode with different flowrates (Mode-D) has not yet been reported. In the present work, a water model for a 120 t ladle is carried out to mainly compare the effect of the two gas blowing modes on mixing. Two porous plugs are located at 0.55-0.70R (R is the radius of ladle bottom), with different relative angles (45-180°) and total flowrates (6.92-18.45 NL/min). The results show that Mode-D can significantly change the mixing time. Compared with Mode-S, the mixing time is respectively decreased by 50 seconds at 6.92 NL/min and 30 seconds at 18.45 NL/min when the plug positions are located at 0.64R. The results of mathematical simulation explain the phenomena. In the Mode-D, the strong gas plume forms a larger circulation flow to stir the ladle and the weak plume forms a smaller one. Under this case, the interference and collision from two plumes are weakened and the dissipation of stirring energy is decreased, thus the mixing time is shortened.

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Section: Mathematical Modeling 221 Control Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Gas Blown Modes on Mixing Phenomena in a Bottom Stirring Ladle with Dual Plugs

Tang

Guo

et al. 2016

ISIJ International

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“…The time elapsed (t) was the same for all samples (20 minutes). The thickness of slag, although it may produce effects in the interaction process between steel and slag 30 , was not considered for study purposes, since during the secondary refining the mass of added slag formers (lime, dolomite, alumina and MgO) in the ladle was practically constant in all the studied heats, being in the range of 2.3 to 2.6 t.…”

mentioning

confidence: 99%

Effective Viscosity of Slag and Kinetic Stirring Parameter Applied in Steel Cleanliness During Vacuum Degassing

Rocha

Pereira

Yoshioka³

et al. 2017

Mat. Res.

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The process of vacuum degassing occurs during the secondary refining of special steels. Its main function is to remove undesirable gases. However, during this process, flotation phenomenon and inclusions absorption are reported. The aim of the present work was to study the slag viscosity and vacuum degassing (tank type) capacity in steel cleanliness from an industry perspective. To achieve this objective, slag and steel samples were taken before and after the vacuum stage. The results in steel cleanliness were related to a kinetic stirring parameter (β s ) of the vacuum station and to the effect of slag viscosity. The removal of inclusions during the vacuum stage reached 64, 75 and 78% in the diameter ranges of 2.5-5, 5-15 and ≥ 15 µm, respectively. After the degassing process, the composition of non-metallic inclusions seemed to approach the slags' chemical compositions. The stirring process in the vacuum degassing station promotes a significant decrease in the inclusion densities for the 2.5-15 µm diameter range and also in the sulfur content in liquid steel. Regarding the effective viscosities of slags, it was concluded that lower values (0.20 Pa.s) increased slag capacity in inclusion removal, whereas higher values (> 0.40 Pa.s) were detrimental to steel cleanliness.

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“…Central to ladle refining operations is vacuum degassing, a process through which the hydrogen and nitrogen content in steel is reduced via tank (vacuum arc degassing, VAD) or recirculating (RH degassing) methods operating under surface pressures close to 10 2 Pa. Mathematical modelling of the flow field in gas-stirred ladles have followed the finite volume computational fluid dynamics (CFD) approach based upon the volume of fluid (VOF) method, 1,2) Euler-Lagrange 3,4) and Eulerian 5,6) methods. The VOF method is an interface tracking technique in which a single set of equations are solved across all phases.…”

Section: Introductionmentioning

confidence: 99%

A Parametric Study on the Effects of Process Conditions on Dehydrogenation, Wall Shear and Slag Entrainment in the Vacuum Arc Degasser Using Mathematical Modelling

et al. 2018

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The effect of vacuum pressure and argon flow rate on hydrogen degassing of molten steel in a triple plug, 100 tonne vacuum arc degasser has been examined using a three phase Eulerian CFD-mass transfer coupled model. The model takes into account the interaction between the slag, steel and argon phases over a 20-minute degassing period. Increasing the argon flowrate from 13-29 Nm 3 hr − 1 produces a 10% increase in the hydrogen removal ratio, generating a faster melt velocity and larger slag eye. This also results in the maximum shear stress on the ladle walls increasing by a factor of 2.2 and the shear stress integrated across the wall increasing by a factor of 3.75, thus contributing to enhance refractory erosion. Within the same flowrate range the volume of entrained slag also increases by a factor of 1.4, which may result in increased nitrogen/oxygen pickup. Reducing the vacuum pressure maintains a low equilibrium hydrogen concentration and allows more efficient hydrogen removal, with a 38% reduction in the removal ratio between 10 2 − 10 4 Pa.

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Multiphase Modeling of Bottom-Stirred Ladle for Prediction of Slag–Steel Interface and Estimation of Desulfurization Behavior

Cited by 41 publications

References 36 publications

Effect of Gas Blown Modes on Mixing Phenomena in a Bottom Stirring Ladle with Dual Plugs

Effect of Gas Blown Modes on Mixing Phenomena in a Bottom Stirring Ladle with Dual Plugs

Effective Viscosity of Slag and Kinetic Stirring Parameter Applied in Steel Cleanliness During Vacuum Degassing

A Parametric Study on the Effects of Process Conditions on Dehydrogenation, Wall Shear and Slag Entrainment in the Vacuum Arc Degasser Using Mathematical Modelling

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