Magnetohydrodynamic Effects on Insulating Bubbles and Inclusions in the Continuous Casting of Steel

Abstract

The magnetohydrodynamic effects associated with a magnetic field perpendicular to the movement of insulating inclusions or bubbles in a conducting liquid are investigated in this article. An increase in drag coefficient as a result of the presence of a magnetic field is argued to have a significant effect on their terminal rise velocity. Inside a continuous steel caster, this lower terminal velocity has a potentially negative effect on the removal rate of unwanted inclusions, degrading the steel quality. Simulations of an insulating rigid sphere moving in the presence of an electrical current show an electromagnetophoretic force per unit volume of À wJ 9 B, with a shape factor w % 1.0. Numerical fluid and dispersed gas phase simulations of the flow inside a submerged entry nozzle show that, because of this force, inhomogeneous magnetic fields can cause nonuniform gas distributions in accordance with a theoretical analysis. In particular, the magnetic field can be tailored to increase or decrease the amount of gas near the side walls.

Distribution and Detriment of Bubbles in Continuous Casting Interstitial Free Steel Slab

“…The interaction between bubbles and inclusions had been studied for long time and many references. [9][10][11] Two main ways of interaction between bubbles and inclusions were acceptable, which also were supported by our present study. (1) Small inclusions followed the bubbles' moving track in their wake; as shown in Fig.…”

Bubble Transport by Electro‐Magnetophoretic Foces at Anode Botttom of Aluminium Cells

“…Some authors [8] introduce form factors to represent different shapes of particles or bubbles compared to the spherical volume expression. The expression in (9), however, is more general.…”

“…Returning to the electrolysis cell situation, it is instructive to analyze the expression (8). We can see that the force increases linearly with the bubble distance y b from the cell centre.…”

“…They suggested possible applications like separation of particles and opposing the gravity effects. Since then metallurgists were keenly exploiting the electro-magnetophoretic force for a variety of applications, such as removal of inclusions from steel melt [7], concentrating the insulating bubbles and inclusions [8], and for many other purposes [9]. It is important to note that not only the electrically conducting particles experience the effect of the electromagnetic force due to the current passing through them and interacting with the overall magnetic field.…”

Dynamic melting and impurity particle tracking in continuously adjustable AC magnetic field

“…The particles travel due to the hydrodynamic drag, buoyancy [5], turbulent fluctuations [6] and the electromagnetic force action via the local pressure distribution around the particle [7]. The time average effects are investigated previously [8][9][10][11], but an incomplete approximation was used which was derived for a locally uniform electric and magnetic fields. The latter contradicts the skin-layer type of the exponential force distribution in the AC field [12,13].…”