Prediction of Emptying Flows in Ladles and Verification with Data from Trace Element Plant Trials.

Grip, Carl-Erik; Jonsson, Lage; Jönsson, Pär G.

doi:10.2355/isijinternational.37.1081

Cited by 17 publications

(19 citation statements)

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“…4) Investigators also developed some simple models to predict the steel temperature in the ladle. [5][6][7][8][9][10] Since most of these models were 2-D, the effect of radiation exchange between surfaces of ladles was not explicitly taken care of. The phenomenon of thermal stratification leads to temperature difference between bulk and outgoing steel during teeming.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Heat Transfer Phenomenon in Steel Making Ladle

et al. 2012

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The control of molten steel temperature is one of the important parameters for producing the superior quality of steel. Ladle is one of the major vessels to be monitored for controlling this temperature. A computational fluid dynamics (CFD) based mathematical model was developed for temperature prediction of ladles and molten steel. The model was validated with data collected from the plant and maximum 4% deviation between predicted and measured data was noticed. The effect of various parameters on temperature drop of molten steel was studied. The results obtained show low impact of slag thickness, tapping temperature and ladle life. However, the importance of initial refractory temperature was noticed. The CFD model developed in present work can generate the history of temperature drop of molten steel and refractory walls of any ladle at any stage. The model can be utilized to predict the suitable tapping temperature.

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Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Heat Transfer Phenomenon in Steel Making Ladle

et al. 2012

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“…[22] However, thinking in terms of the present problem, we must expect high velocity and temperature gradients along the ladle walls and its bottom, as has been reported by research that preceded the present work. [12][13][14][15][16][17][18] Then, it may be very helpful and suitable, for the purposes outlined previously, to choose a model that behaves like a k-model in the inner region of the boundary layer, where high velocity and temperature gradients are expected, and at the same time, out of the boundary layer, it behaves like a high Reynolds k-model ( Figure 1). The turbulence model that satisfies this expectation is known as the shear stress transport (SST) k-model, or simply the SST k-model.…”

Section: The Mathematical Modelmentioning

confidence: 98%

“…Longer standstill times cause lower start casting temperatures and large steel throughputs lead to smaller temperature loses. Grip et al [13,14,15] studied thermal stratification of steel using the mixing kinetics of copper and vanadium employed as chemical tracers in a steel ladle. These authors found that argon stirring during short times such 2 to 3 minutes, at the usual flow rates, was enough to eliminate thermal stratification.…”

Section: Introductionmentioning

confidence: 99%

Mathematical simulation of fluid dynamics during steel draining operations from a ladle

Davila

García-Demedices

Morales

2006

Metall Mater Trans B

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Fluid flow dynamics during ladle drainage operations of steel under isothermal and nonisothermal conditions has been studied using the turbulence shear stress transport k-model (SST k-) and the multiphase volume of fluid (VOF) model. At high bath levels, the angular velocity of the melt, close to the ladle nozzle, is small rotating anticlockwise and intense vertical-recirculating flows are developed in most of the liquid volume due to descending steel streams along the ladle vertical wall. These streams ascend further downstream driven by buoyancy forces. At low bath levels, the melt, which is close to the nozzle, rotates clockwise with higher velocities whose magnitudes are higher for shorter ladle standstill times. These velocities are responsible for the formation and development of a vortex on the bath free surface, which entrains slag into the nozzle by shear-stress mechanisms at the metal-slag interface. The critical bath level or bath height for this phenomenon is 0.35 m (in this particular ladle design) for a ladle standstill time of 15 minutes and decreases with longer ladle standstill times. At these steps, the vertical-recirculating flows are substituted by complex horizontal-rotating flows in most of the liquid volume. Under isothermal conditions, the critical bath level for vortex formation on the melt free surface is 0.20 m, which agrees very well with that determined with a 1/3 scale water model of 0.073 m. It is concluded that buoyancy forces, originated by thermal gradients, as the ladle cools, are responsible for increasing the critical bath level for vortex formation. Understanding vortex mechanisms will be useful to design simple and efficient devices to break down the vortex flow during steel draining even at very low metal residues in the ladle.

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“…27) They found that time-related tracer concentration curves determined experimentally agreed very well with the numerical predictions. Grip et al 29) also modeled the addition of tracer elements during the teeming process and compared with experiments. The agreement between plant measurements and predictions was also good in that study.…”

Section: • Alloyingmentioning

confidence: 99%

The Use of Fundamental Process Models in Studying Ladle Refining Operations.

Jönsson

Jonsson

2001

ISIJ International

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Existing fundamental models of ladle refining operations have been reviewed. No fundamental model that takes all the individual parts of ladle refining into account has been found in the open literature. Nor does a model exist which considers all refining in only one part of a refining step such as vacuum treatment. However, separate fundamental models for prediction regarding alloying, temperature, hydrogen, sulfur, reoxidation, and inclusion growth and removal do exist. In one case, a reoxidation model has also been combined with a sulfur-refining model. Predicted values from the separate models for alloying, temperature, sulfur and hydrogen have been found to agree well with corresponding measured data. The verification of the models for reoxidation and the growth and removal of inclusions is currently lacking and separate models for refining operations such as nitrogen or carbon removal need to be developed. Also, more complex models of parts of ladle refining such as vacuum treatment need to be developed, incorporating the sulfur, hydrogen, reoxidation and inclusion growth and removal models. The ultimate goal is, of course, one overall model that can predict desired parameter values for all steps of ladle refining. Even though such a model does not exist today, the usefulness of existing fundamental models is exemplified. This is to illustrate the potential of more complex and more realistic ladle models in process optimization.KEY WORDS: secondary refining; ladle; modeling; fundamental; steel; slag and gas.tration gradient of the element exists at the interface between two phases. This can, for example, be in the steel phase, if the diffusion of the solutes to be removed or added in steel is the rate controling step. Furthermore, it is assumed that the phases on each side of the concentration boundary layer, the steel phase and the refining phase (gas for hydrogen removal and slag for sulfur removal), are steadily and completely mixed. Therefore, the removal rate of an impurity elements from steel can, for example, be described as follows: 5) ................. (1) where x is the element to be refined (i.e. S or H), k is the total mass-transfer coefficient, r is the steel density, M is the steel mass, and [%x] is the actual concentration of the element to be refined. The parameter [%x] e is the hypothetical concentration of the refined element in the steel phase in equilibrium with the actual concentration in the refining phase. "A" is the interfacial area between the steel and the phase to which the element is refined. In the cases of hydrogen refining and sulfur refining, this is the gas phase and slag phase, respectively.One disadvantage with this traditional approach is that due to the assumptions mentioned, more often than not the coefficients in Eq. (1) can only be valid for one specific case at a time. Therefore, this equation tends to be of limited usefulness in prediction for refining processes in general. For example, the interfacial area A, to be used in prediction of desulfurization during gas...

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Prediction of Emptying Flows in Ladles and Verification with Data from Trace Element Plant Trials.

Cited by 17 publications

References 0 publications

Numerical Simulation of Heat Transfer Phenomenon in Steel Making Ladle

Numerical Simulation of Heat Transfer Phenomenon in Steel Making Ladle

Mathematical simulation of fluid dynamics during steel draining operations from a ladle

The Use of Fundamental Process Models in Studying Ladle Refining Operations.

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