The Peculiarities of Convective Heat Transfer in Melt of a Multiple-Electrode Arc Furnace

The modern direction of improving the technology of steel production in high-power arc furnaces is the intensification of magnetohydrodynamic effects for mixing the melt. In this article, a furnace design is proposed that contains three roof arc and three bottom electrodes, which provides the formation of additional eddy currents in the melt when the furnace is supplied with direct current or a low-frequency current. For a numerical study of the features of heat transfer in the melt of this furnace, a three-dimensional mathematical model of magnetohydrodynamic and thermal processes was used. The results were processed using the methods of visualization of vortex structures and the Richardson criterion. In an oven with a capacity of 180 tons at currents in the electrodes of 80 kA, the conditions for the interaction of electric vortex and thermogravitational convection were studied. Results showed that thermogravitational convection due to nonuniform heating of the melt led to a decrease in the size of the main electric vortex flow and the formation of an additional flow near the side walls of the furnace. The features of azimuthal flows formed in the areas of electric arcs and hearth electrodes were analyzed. Results showed that the multivortex structure of the flows that formed in the furnace allowed the volume of stagnant zones to be reduced and provided acceptable melt mixing conditions. The results can be used to improve the energy and structural parameters of three-electrode arc furnaces.

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Characteristics of convective heat transfer in the melt of multi-electrode arc furnace

Vestnik IGEU ◽

10.17588/2072-2672.2020.2.013-022 ◽

2020 ◽

pp. 13-22 ◽

Cited By ~ 1

Author(s):

A.L. Kukharev

Keyword(s):

Three Dimensional ◽

Steel Production ◽

Azimuthal Velocity ◽

Design Parameters ◽

Melt Mixing ◽

Electric Arcs ◽

Thermogravitational Convection ◽

Arc Furnaces ◽

Calculation Results ◽

Uneven Heating

The modern direction of improving the technology of steel production in high-power arc furnaces is the intensification of magnetohydrodynamic effects for melt mixing. In this regard, it is relevant to study the characteristics of heat trans-fer in the melt of this furnace, taking into account the interaction of electrovortex and thermogravitational convection. The results were obtained using a three-dimensional mathematical model of magnetohydrodynamic and thermal pro-cesses, constructed using a non-inductive approximation, taking into account the k- turbulence model. As heat-generating sources, the model takes into account the heat flows from electric arcs and Joule heating. Processing of the results was carried out using visualization methods of vortex structures. A furnace design containing three arched and three bottom electrodes and providing the formation of additional electrovortex flows in the melt is proposed. It is shown that under the given simulation conditions and currents in 80 kA electrodes a multivortex flow is formed in the furnace melt as a result of the interaction of electrovortex and thermogravitational convection. Electrovortex convection dominates near the bath axis. Thermogravitational convection, due to uneven heating of the melt, leads to a reduction in the size of the main electrovortex flow and the formation of an additional flow near the side walls of the furnace. Maximum speeds of 2 m/s are fixed in the melt areas under electric arcs. In this case, the speed of the downward flow under the electric arcs decreases, and the speed of the upward flow in the region of the bottom elec-trodes increases. The effect of thermogravitational convection on the azimuthal melt flow is manifested mainly in the region of the bottom electrodes, leading to an increase in the azimuthal velocity and displacement of the vortices to the center of the bath. The verification of the proposed model was carried out by comparing the calculation results with the experimental data obtained in laboratory installations with various electrode arrangements. The results will be used to further improve the energy and design parameters of arc furnaces.

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Numerical Study of Turbulent Flows and Heat Transfer in Coupled Industrial-Scale Tundish of a Continuous Casting Material in Steel Production

Numerical Simulations in Engineering and Science ◽

10.5772/intechopen.75935 ◽

2018 ◽

Author(s):

Jose Adilson de Castro ◽

Bruno Amaral Pereira ◽

Roan Sampaio de Souza ◽

Elizabeth Mendes de Oliveira ◽

Ivaldo Leão Ferreira

Keyword(s):

Heat Transfer ◽

Continuous Casting ◽

Turbulent Flows ◽

Numerical Study ◽

Steel Production ◽

Industrial Scale

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Theoretical and numerical study of nonlinear acoustic absorbers for low frequency noise control

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-3171 ◽

2021 ◽

Vol 263 (1) ◽

pp. 5600-5604

Author(s):

Min Yang ◽

Xianhui Li ◽

Zenong Cai ◽

Junjuan Zhao ◽

Peng Zhang ◽

...

Keyword(s):

Sound Absorption ◽

Averaging Method ◽

Numerical Study ◽

Structural Parameters ◽

Low Frequency ◽

Frequency Noise ◽

Flow Equations ◽

State Response ◽

Runge Kutta Method ◽

Absorption Performance

In this paper, the sound absorption characteristics of cubic nonlinear sound-absorbing structures are analyzed by theoretical and numerical methods. The slow flow equations of the system are derived by using complexification averaging method, and the nonlinear equations which describe the steady- state response are obtained. The resulting equations are verified by comparing the results which respectively obtained from complexification-averaging method and Runge-Kutta method. It is helpful to optimize the structural parameters and further improve the sound absorption performance to study the variation of the sound absorption performance of cubic nonlinear structure with its structural parameters.

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Design of a radiative heat recuperator for steel processes

MATEC Web of Conferences ◽

10.1051/matecconf/202033001034 ◽

2020 ◽

Vol 330 ◽

pp. 01034

Author(s):

Peru Fernandez Arroiabe ◽

Jon Iturralde Iñarga ◽

Mercedes Gómez de Arteche Botas ◽

Susana López Pérez ◽

Eduardo Ubieta Astigarraga ◽

...

Keyword(s):

Heat Transfer ◽

Heat Transfer Rate ◽

Transfer Rate ◽

Waste Heat ◽

Numerical Study ◽

Steel Production ◽

Flow Distribution ◽

Radiative Energy ◽

Production Plant ◽

Heat Recuperator

In recent years, there has been an increasing interest in the recovery of the waste heat of steel and glass processes. This work proposes a numerical study of a waste heat exchanger system for steel production processes. The radiative energy is transferred to a commercial oil, which can be used to produce electricity. The behavior of the recuperator is analysed using a 3D numerical model, considering the constrains of a real production plant. The influence of the radiation properties of the materials on the temperature and heat transfer rate are also examined. The results show that the absorptivity of the tubes influences significantly the absorbed waste heat. Furthermore, heterogeneous mass flow distribution should be applied to optimize the total heat transfer rate.

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Numerical Study of Nonlinear and Transient Behaviors of a Variable Electromotive-Force Generator With an Adjustable Overlap Between the Rotor and the Stator Using the Finite Element Method

Volume 4B: Dynamics, Vibration, and Control ◽

10.1115/imece2014-38755 ◽

2014 ◽

Author(s):

J. Agbormbai ◽

N. Goudarzi ◽

W. D. Zhu

Keyword(s):

Finite Element ◽

Electromotive Force ◽

Eddy Currents ◽

Numerical Study ◽

Fuel Efficiency ◽

Low Frequency ◽

Fixed Number ◽

Three Dimensional Model ◽

Hexahedral Elements ◽

Force Generator

A modified generator, referred to as the variable electromotive-force generator, is developed to enhance fuel efficiency of hybrid vehicles and expand operational range of wind turbines. Obtaining a numerical model that provides accurate estimates on the generator output power at different overlap ratios and rotor speeds, comparable with those from experimental results, would expand the use of the proposed modified generator in different applications. The general behavior of the generated electromotive forces at different overlaps and rotor speeds is in good agreement with those from experimental and analytical results at steady-state conditions. Employing generator losses due to hysteresis and eddy currents in a three-dimensional model would generate more realistic and comparable results with those from experiment. In this work, electromagnetic analysis of a modified two-pole DC generator with an adjustable overlap between the rotor and the stator at transient conditions is performed using finite element simulation in the ANSYS 3D Low Frequency Electromagnetics package. The model is meshed with tetrahedral or hexahedral elements, and the magnetic field at each element is approximated using a quadratic polynomial. For a fixed number of coils, two cases are studied; one with constant magnetic properties and the other with nonlinear demagnetization curves are studied.

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