Control of flow field and steel slag interface in FTSC mold under electromagnetic braking
Aiming to solve the problem of the instability of the flow field and steel slag surface in the thin slab con-tinuous casting mold under high casting speed,the FTSC(flexible thin slab caster)mold and MM-EMBr(multi-module electromagnetic braking)system of a steel company were used as research objects,the LES and VOF model were used as numerical simulation to perform multi physics field coupling calculation on the flow field of mold under different electromagnetic induction intensity,the key is to study the effect of different magnetic induction intensities on the flow field inside the mold and the steel slag interface under the conditions of immersion depth of 190 mm and casting speed of 6 m/min.The results show that without electromagnetic braking,the flow field inside the mold gradually changes from the initial double circulation mode to a single circulation mode as the impact depth increases,the steel slag interface is unstable and fluctuates greatly,the maximum velocity of the steel slag interface exceeds 0.65 m/s,and the maximum wave height exceeds 40 mm,slag entrapment and slag holes appear at the steel slag interface,part of the turbulent kinetic energy of the upflow molten steel is converted into potential energy,which makes the position of the steel slag interface rise gradually and makes the liquid slag layer thinner;after the MM-EMBr system is turned on,when the magnetic induction intensity at position C directly below the SEN is not less than 0.09 T,the speed and angle of the main jet can be effectively controlled to make the impact point of the narrow wall fluctuate up and down within a certain range,so as to control the flow field in the mold;with the increase of magnetic induction intensity,the total turbulent kinetic energy in the mold gradually decreases,when the magnetic induction intensity of AB,C,DE increases to 0.17,0.15,0.12 T,the maximum velocity of steel slag interface can be controlled within 0.30 m/s,the maximum wave height can be controlled within 10 mm,the average height of steel slag interface position is controlled within-2-2 mm,and the turbulent kinetic energy of steel slag interface can be controlled within 0.045 J/kg,this electromagnetic braking intensity is the most effective,and the flow field in the mold and the steel slag interface are relatively stable;when the magnetic induction intensity continues to increase,the turbulent kinetic energy in the mold and at the steel slag interface increases instead,it shows that the stronger the magnetic induction intensity is,the more ineffective it is,the best braking effect can be achieved only by the coopera-tion of all modules.
electromagnetic brakingthin slab moldsteel slag interfaceslag entrapmentturbulence kinetic energy
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