Electrovortex Flow Research Articles

Influence of the swirled electrovortex flow on the melting of eutectic alloy In-Ga-Sn

Influence of the swirled electrovortex flow on the melting of eutectic alloy In-Ga-Sn

The relevance of melt convection to grain refinement in Al–Si alloys solidified under the impact of electric currents

This paper considers the directional solidification of Al–7wt.% Si alloys under the influence of strong electric currents for the configuration of two parallel electrodes immersed from the free surface into the solidifying alloy. Solidification experiments were performed under the influence of both direct currents (DC) and rectangular electric current pulses (ECP). The interaction between the applied current and its own induced magnetic field causes a Lorentz force, which produces an electro-vortex flow covering the entire melt area. Numerical simulations of the magnetohydrodynamic problem were conducted to calculate the Lorentz force, Joule heating and induced melt flow. The numerical predictions were confirmed by isothermal flow measurements in eutectic Ga–20wt.% In–12wt.% Sn. The application of the electric current during solidification leads to the formation of refined equiaxed grain structures. There are no remarkable differences with respect to the influence of DC or ECP treatment on the mean grain size and the area of equiaxed zone in the solidified samples, provided the effective values of the current strength are identical. The results demonstrate that the grain refining effect observed in these experiments can be ascribed solely to the forced melt flow driven by the Lorentz force.

Modelling of electro-vortex flows in the DC electric arc furnace with different bottom scheme

Modelling of electro-vortex flows in the DC electric arc furnace with different bottom scheme

Numerical modelling of electrovortex and heat flows in dc electric arc furnace with cooling bottom electrode

The article is devoted to the numerical modelling of electrovortex and convection flows in DC electric arc furnace with the cooling bottom electrode. The shear stress on the fettle area are offered as criteria for the estimation of vortex flows influence on the increased wearing of fettle. It is shown that cooling down the bottom electrode to the melting metal temperature leads to decrease of shear stress on the fettle area by 15 %.

Modelling of electrovortex and heat flows in dc arc furnaces with bottom electrode

The article is devoted to the investigation of interaction between electrovortex and heat flows of liquid metal in dc arc furnaces with a bottom electrode. A mathematical model of liquid steel flows in a dc arc furnace with a bottom electrode was developed, and an algorithm of a three-stage solution was produced based on standard software packages. The results of electromagnetic, heat transfer and hydrodynamic analysis in industrial dc arc furnaces are given. It is shown that the Lorentz force makes up ∼30% of the volumetric gravity force and makes the main contribution to vortex flow of liquid metal in a dc arc furnace. The convection flows with the maximum heat power of furnace make a significant contribution to the vortex flow of liquid metal, and the maximum value of the vortex flow velocity is ∼1·5 times more than the movement without convection. The verification of results has been carried out by comparing them with general electrovortex flows theory, experimental data and results of similar software packages.

Modeling of Vortex Flows in Direct Current (DC) Electric Arc Furnace with Different Bottom Electrode Positions

This article is devoted to the numerical modeling of electrovortex and convection flows in the direct current (DC) electric arc furnace with a different position of the bottom electrode. The electromagnetic, temperature, and hydrodynamic distribution parameters are given. The shear stress on the fettle area is offered as a criterion for the estimation of vortex flow influence on the increased wearing of the fettle. It is shown that lifting the bottom electrode above the fettle surface at the electrode radius leads to the decrease of shear stress on the fettle area by 30 pct. Putting the bottom electrode lower than the fettle surface by the distance equal to the electrode radius and its expanding by the same distance reduces the stress by 10 pct.

Effect of the technological parameters of the melt treatment by a electric pulse current on the mixing process

The capacitive storage voltage, the storage capacity, the discharge circuit’s inductance, and the electrode system’s type, along with the pulse current’s strength, are shown to be the important technological parameters defining the character of the electrovortex flows, the magnetic pressure, and the liquid-metal conductor mixing speed during the passing of a pulse current. The most effective system among those investigated for cylindrical conductor treatment is the system “point-to-point” providing the intensive mixing of the melt, a favorable structure, and an improved complex of the mechanical properties of alloys after crystallization.

The problem of swirling of axisymmetric electrovortex flows

The problem of swirling of axisymmetric electrovortex flows

Pumping effect in a flat MHD channel with an electrovortex flow

Pumping effect in a flat MHD channel with an electrovortex flow

COLLAPSE, SYMMETRY BREAKING, AND HYSTERESIS IN SWIRLING FLOWS

▪ Abstract The paper reviews striking features of swirling flows—collapse, swirl generation, vortex breakdown, hysteresis, and axisymmetry breaking—and the mechanisms involved with the help of conical similarity solutions of the Navier-Stokes equations. The strong accumulation of axial and angular momenta, observed in tornadoes and flows over delta wings, corresponds to collapse, i.e. the singularity development in these solutions. Bifurcation of swirl explains the threshold character of swirl development in capillary and electrovortex flows. Analytical solutions for fold catastrophes and hysteresis reveal why there are so few stable states and why the jump transitions between the states occur—features typical of tornadoes, of flows over delta wings, and in vortex devices. Finally, the divergent instability explains such effects as the splitting of a tornado and the development of spiral branches in tree and near-wall swirling flows.

Electromagnetic processes in liquid material in the USSR and East European countries.

The influence of electromagnetic fields on electrically conducting liquid materials is a complex phenomenon attracting more and more interests of specialists in the fields of metallurgy, technology, energetics, medicine and geophysics. The major part of the phenomena concerning the movement of electrically conducting liquid media in electromagnetic fields is studied by magnetohydrodynamics (MHD) which is comparatively a new branch of the science based on the principles of electrodynamics and mechanics of continuous media. In USSR, MHD has passed the full scale distance of the development practically covering all the known fields of the science. This discipline obliged notably, not only by its successes to the development of the MHD method for the generation of electric power, but also by the development of MHD theory and MHD technology in metallurgy and material science which have enriched MHD with new ideas and turned it into productive force helping it out of the sphere of abstractions.The current review of basic Soviet publications obviously appears for the first time in the Western journals and demonstrates the uneasy way for MHD and the main achievements along the way of MHD developed. The extremely great value of information containing in Soviet publications on hydrodynamics of conducting media can not be in essence concentrated in the style of a journal article. Nevertheless, it is possible to mark out the main fields, where the most significant results have been achieved.1) Magneto-hydraulics and -hydromechanics including those in strong magnetic fields2) MHD turbulence3) MHD machinery (pumps, generators, throttles)4) MHD technology of liquid metalBeside of these usual sections of modern MHD, there are some new sections which have appeared comparatively recently in the USSR. They are electrovortex flows where current in liquid material interacts with the magnetic field induced by the current and capillary MHD-flows which is a small-scale MHD flow with a small-scale boundary and with strong surface forces at the boundary. Appearance of such new sections is first of all obliged to penetrate into MHD and the series of engineering sciences in electrometallurgy and electric welding mutually. Such an interfusion guarantees us the development of MHD in the future.