Multi-Physics Modeling of Steel Ingot Melting by Electric Arc Plasma and its Application to Electric Arc Furnace

Abstract

Arc melting is one of the commonly-used melting methods in modern material manufacturing. The present study established a numerical model coupling the electric arc plasma, solid melting, and liquid flow together to simulate the steel ingot melting process using the electric arc. The direct current electric arc behavioral characteristics with varying arc length generated by the moving electrode were analyzed based on the validated model. The effects of both the initial arc length and the dynamic electrode movement on the steel ingot melting efficiency were studied. A potential method was also proposed to apply the established model in simulating the electric arc furnace scrap melting. The study reveals that a reasonable and stable arc length can provide higher instantaneous heat flux and current density and reduce the arc dissipation, meanwhile balance the electrode consumption rate and melting efficiency to achieve the highest economic benefit. In addition, the dynamic electrode movement during the melting process maintains the original arc performance near the ingot top surface, which also results in a positive impact on the melting efficiency.

Effects of EAF Operations on Water‐Cooling Panel Overheating

“…In industrial‐operating condition, arc plasma will influence the flow field significantly by accelerating it. [ 33 ] In this article, the arc plasma is considered by adding a fixed velocity of 1000 m s −1 in vertical direction to simulate a more proper flow field.…”

Numerical investigation of AC electric arc plasma heat dissipation in EAF

“…1) The electric arc plasma is treated as an incompressible Newtonian fluid with temperature-dependent thermodynamic properties [6][7][8][9]16].…”

“…2) The electric arc plasma is optically thin and in a state of local thermodynamic equilibrium (LTE), that is, the temperature of the electron can be approximated as the temperature of heavy particles [6][7][8][9]16]. This assumption is valid in most regions within the arc column, except in the fine sheath close to the cathode/anode surface since the electron temperature there needs to be higher to maintain a conductor path between the arc column and the surface.…”

“…Therefore, the catholic white-hot spot is assumed to be fixed at the centre of the cathode/anode surface for a better boundary condition allocation and future quantitative analysis [17,18]. 4) The gravity effect is ignored for all cases in the present study since the magnitude of electric arc plasma weight is much smaller compared with that of the axial pressure gradient during arcing [6][7][8][9][16][17][18][19].…”

“…During the arc melting process in the EAF, thermionic electrons excited by the voltage difference between the graphite electrode tip and the scrap surface repeatedly collide with gas molecules in their travel path and trigger the ionization of the gas, thereby producing a high-temperature electric arc plasma. The intensive electrical arc plasma is considered as the key to transforming the electrical energy into heat, whose amount of heat-releasing accounts for 65-85% of the total energy input in EAF [4,5]. The heat from the arc will be dissipated in the form of convection, radiation and electron flow to serve the purpose of heating and melting the steel scrap mixes.…”