STUDY OF THE BEHAVIOR OF CURRENT-CARRYING LIQUID IN THE BATH OF DC ARC FURNACE BY AN EXTERNAL VERTICAL MAGNETIC FIELD ON A PHYSICAL MODEL

I M Yachikov,I V Portnova,T P Larina

doi:10.17073/0368-0797-2018-1-28-34

Abstract

When an external vertical magnetic field is applied to a current-carrying melt in the bath of a DC arc furnace, volumetric electromagnetic forces arise that drive it. Flows of metal and slag occur in the bath of the DC arc furnace. This can lead to their efficient mixing, but can also carry negative aspects,for example, associated with an increase in wear oflining in the region of the bottom electrode. The processes of conductive mixing in the bath of the DC arc furnace during smelting of metals and alloys remain poorly understood, there arise both theoretical questions related to the nature of the flows in the bath under the action of external and intrinsic magnetic fields of a given intensity, and practical with the absence of simple and reliable sources of external magnetic fields. The purpose of this paper isto qualitatively test the capabilities of a physical model, to study the nature of currents of a current-carrying liquid under the action of an external vertical magnetic field, and to analyze the possibility of transferring simulation results to processes occurring in a five-ton bath of an industrial DC arc furnace. The principal possibility of studying the current flow behavior of a current-carrying melt under the influence of external magnetic fields on models using non-metallic electrically conducting transparent liquids is shown. In this work the authors have used a water solution of table salt, it allowed to estimate the velocity of the liquid on itsfree surface and near the bottom electrode using video. The physical modeling of the effect of an external vertical magnetic field on the current flowing current in a bath was carried out for different combinations of connecting the bottom electrode and different currents flowing through the bath. The current flowing current in the bath under the influence of an external vertical magnetic field was established when the central electrode or the bottom electrode is displaced from the axis of the bath. It was revealed that when the axis of the bottom electrode is displaced from the bath axis, the average rotation speed of the liquid in the horizontal plane increases. An estimate of the value of the vertical magnetic field strength (about 5 kA/m) is obtained, which should be accompanied by conductive mixing the metal bath of the five-ton steel-smelting arc furnace.

Highlights

When an external vertical magnetic field is applied to a current-carrying melt in the bath of a DC arc furnace, volumetric electromagnetic forces arise that drive it
The purpose of this paper is to qualitatively test the capabilities of a physical "transparent" model, to study the nature of currents of a current-carrying liquid under the action of an external vertical magnetic field, and to analyze the possibility of transferring simulation results to processes occurring in a five-ton bath of an industrial DC arc furnace
The physical modeling of the effect of an external vertical magnetic field on the current flowing current in a bath was carried out for different combinations of connecting the bottom electrode and different currents flowing through the bath

Summary

Geometrical parameters of the model bath and the current supplies

Мм Диаметр подины, мм Диаметр ванны по жидкости, мм Высота ванны, мм Диаметр катода в месте контакта с жидкостью, мм Угол откоса ванны, мм Расстояние между осями подовых электродов и ванны, мм. 3. Движение жидкости в ванне при подключении одного смещенного от оси подового электрода: а – модельная ванна с «маячками» в виде твердых частиц при анализе характера течения вблизи подины; б – модельная ванна с «маячками» в виде мелких кусочков бумаги при измерении скорости жидкости на ее поверхности; 1 – ванна; 2 – электролит; 3 – катод; 4 – анод; 5 – измерительный сектор; 6 – место расположения подового электрода; → – направление движения жидкости. Ось которого совпадает с осью ванны, при тех же параметрах тока и внешнего магнитного поля, что и при смещенном от оси ванны на ΔL подовом электроде, течение жидкости более слабое. При приближении к боковой стенке скорость жидкости снижается и визуально наблюдается застойная зона, размер которой уменьшается по мере увеличения тока через ванну и (или) внешнего магнитного поля. Количественные измерения скорости жидкости проводились на ее свободной поверхности при подключении подового электрода, смещенного от оси ванны. Количественно скорость жидкости на ее свободной поверхности определялась из наблюдения за движением «маячков», в качестве которых использовались мелкие твердые частицы, образующиеся при разрушении электролизом электродов или мелкие кусочки бумаги (рис. 3, б)

Определялось количество кадров при прохождении

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