Effect of Arc Length on Fluid Flow and Mixing Phenomena in AC Electric Arc Furnaces

Gonzalez, O. J. P.; Ramírez-Argáez, Marco A.; Conejo, Alberto N.

doi:10.2355/isijinternational.50.1

Cited by 25 publications

(28 citation statements)

References 6 publications

(9 reference statements)

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“…This is in good agreement with the works done previously on natural convection in an EAF. 16,17) However, in a real process, the stratification is less pronounced due to disturbances in the EAF, for example, motion included by oxygen lancing, alloying and CO bubbling. In contrast, when electromagnetic stirring is used, the temperature is homogenized inside the melt, and the superheated region close to the arc spots disappears.…”

Section: Effect Of Stirring On Melting Of the Scrapmentioning

confidence: 99%

Mathematical Modeling of Scrap Melting in an EAF Using Electromagnetic Stirring

et al. 2013

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Numerical modeling has been used to investigate the influence of electromagnetic stirring on melting of a single piece of scrap in an eccentric bottom tapping (EBT) electric arc furnace (EAF). The heat transfer and fluid flow in the melt for both conditions with and without electromagnetic stirring were studied. The buoyancy and electromagnetic forces were considered as the source terms for momentum transfer in the studied conditions. The enthalpy-porosity technique was applied to track the phase change of a scrap piece defined in the EBT region of the furnace. Different scrap sizes, preheating temperatures, stirring directions and force magnitudes were considered, and the heat transfer coefficient was estimated from the heat transfer rate at the melt-scrap interface. The results showed that electromagnetic stirring led to a reduced melting time and an increased heat transfer coefficient by a factor of four. The results for Nusselt number versus Grashof number for natural convection and Reynolds number for electromagnetic stirring were compared with those obtained through correlations from previous studies.

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Section: Effect Of Stirring On Melting Of the Scrapmentioning

confidence: 99%

Mathematical Modeling of Scrap Melting in an EAF Using Electromagnetic Stirring

et al. 2013

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“…The first two models have been reported elsewhere 16,17) and only a brief description will be outlined below. An important feature of these models is the computational domain shown in Fig.…”

Section: Description Of Mathematical Modelmentioning

confidence: 99%

“…Fluid Flow Model: This model 17) was developed to compute velocity and temperature fields in the entire com-…”

Section: )mentioning

confidence: 99%

Mathematical Modeling of the Melting Rate of Metallic Particles in the Electric Arc Furnace

2010

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A computational fluid dynamics model coupled to a lagrangian model of melting/solidifying particles has been developed to describe the melting kinetics of metallic particles in an industrial Electric Arc Furnace (EAF), assuming that liquid steel occupies the entire computational domain. The metallic particles represent Direct Reduced Iron (DRI). The use of two previous models, an arc model and a fluid flow model has made possible to evaluate the melting rate of injected DRI in a three phase-EAF, evaluating the influence of the initial particle size, the initial DRI temperature, feeding position, feeding rate, arc length and some of the metallurgical properties of DRI. The frozen shell formed in the early stage of the melting process has also been evaluated in this model. KEY WORDS: DRI melting; CFD; melting rate. 9© 2010 ISIJ that the thickness of the frozen shell is negligible in comparison with the radius of the particle, therefore, in the thermal balance the radius employed is not the radius at the liquid-particle interface but the initial particle radius, as follows:.............. (1) Sato et al. 6,7) reported laboratory experimental results from the melting of pre-reduced pellets in liquid steel and in molten slags. They found an increase in the melting rate by increasing metallization of pellets and by increasing the temperature of the molten bath, however, once the temperature reaches 1 570°C a further increase has no significant effect on the melting rate.Aboutalebi et al. 8) reported the influence of particle size, temperature and stirring conditions on the melting rate of metallic particles in a ladle. In this work the formation of the solid shell was neglected. They concluded that the melting rate increases by decreasing the particle size and by increasing both superheat temperature and stirring conditions. Similar results have been reported by Jiao and Themelis 9) and Ji et al. 10)Zhang and Oeters 11) described a mathematical model to represent the melting process of ferromanganese particles thrown into a steel ladle. They found a short time, less than 1 s, to reach the terminal velocity inside the melt and such velocity was used to compute the heat transfer coefficient. A melting distribution time to represent the melting rate of all particles was used to define the melting time of a variable particle distribution. It was found a higher melting rate as both the terminal velocity and melt temperature increases.Several works have been reported on scrap melting in Electric Arc Furnaces (EAF). Matson and Ramirez 12) investigated the melting process of scrap assuming spherical iron particles. Gaye et al. 13) suggested a maximum scrap size of 120 mm in the converter to avoid unmelted scrap at the end of the blow. Szekely et al. 14) attributed a key role to carbon dissolved in liquid steel to facilitate scrap melting. Li et al. 15) used steel bars with various sizes to describe scrap melting.An integral approach coupling heat, mass and fluid flow phenomena to understand the DRI melting and dissolu...

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“…2) ε 1 , ε 2 , ε 3 and ε 4 were obtained from; 19) H2O , C p,roof and C p,wall were obtained from; 2,20,21) λ sSc and λ sSl were obtained from, 12) K therm4 , K therm7 and K therm8 were obtained from approximate heat transfer coefficients for steel and slag 7,9,10) normalized to the specific EAF properties (dimensions), while K water1 , K water2 , K water3 , K water4 and K water5 were obtained from approximate heat transfer coefficients for furnace walls 7) normalized to the specific EAF dimensions. …”

Section: Appendixmentioning

confidence: 99%

“…(32)). Coefficient Ktherm4 was obtained from the approximate heat transfer coefficient for steel 7,9,10) taking into account the properties of the specific EAF. Together with fraction this factor accounts for decreasing heat transfer to the gas zone with decreasing mass of solid steel.…”

Section: Solid Scrap Zone (Ssc)mentioning

confidence: 99%

Modeling and Validation of an Electric Arc Furnace: Part 1, Heat and Mass Transfer

2012

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The following paper presents an approach to the mathematical modeling of heat and mass transfer processes in a 3-phase, 80 MVA AC, electric arc furnace (EAF) and represents a continuation of our work on modeling the electric and hydraulic EAF processes. This paper represents part 1 of the complete model and addresses issues on modeling the mass, temperature and energy processes in the EAF, while part 2 of the paper focuses solely on the issues related to the thermo-chemical relations and reactions in the EAF. As is generally known, the chemical, thermal and mass processes in an EAF are related to each other and cannot be studied completely separately; therefore, the work presented in part 1 and part 2 is related to each other accordingly and should be considered as a whole. The presented sub-models were obtained in accordance with different mathematical and thermo-dynamic laws, with the parameters fitted both experimentally, using the measured operational data of an EAF during different periods of the melting process, and theoretically, using the conclusions of different studies involved in EAF modeling. In conjunction with the already presented electrical and hydraulic models of the EAF, the heat-, mass-and energy-transfer models proposed in this work represent a complete EAF model, which can be further used for the initial aims of our study, i.e., optimization of the energy consumption and development of the operator-training simulator. The presented results show high levels of similarity with both the measured operational data and the theoretical data available in different EAF studies, from which we can conclude that the presented EAF model is developed in accordance with both fundamental laws of thermodynamics and the practical aspects regarding EAF operation.

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Effect of Arc Length on Fluid Flow and Mixing Phenomena in AC Electric Arc Furnaces

Cited by 25 publications

References 6 publications

Mathematical Modeling of Scrap Melting in an EAF Using Electromagnetic Stirring

Mathematical Modeling of Scrap Melting in an EAF Using Electromagnetic Stirring

Mathematical Modeling of the Melting Rate of Metallic Particles in the Electric Arc Furnace

Modeling and Validation of an Electric Arc Furnace: Part 1, Heat and Mass Transfer

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