Numerical Calculation On Collision-Coalescence Of Inclusion In The Bloom Continuous Casting Mold With Electromagnetic Stirring

Electromagnetic stirring technology can improve the quality of casting slab and improve the quality of continuous casting,which is one of the key technologies of continuous casting steel.Mold metallurgy is a complex process of liquid metal solidification involving many complex phenomena,which involves a variety of complex phenomena such as flow field,heat transfer temperature field,mass transfer concentration field and so on.In this paper,we use the ANSYS and CFX software to solve the coupling problem of the magnetic field and the flow field under the electromagnetic stirring.On the basis of the mass concentration and mass conservation model,the collision-growth behavior of inclusions in molten steel under mold electromagnetic stirring was analyzed.The relevant mathematical model can be divided into three parts:electromagnetic field,MHD flow and collision-coalescence among inclusions in the bloom continuous caster with M-EMS.The following conclusions are drawn:(1)In the absence of electromagnetic stirring,the velocity distribution along the radial direction,the velocity on the center of the molten steel is very small,the maximum velocity are in the center of the slab;The velocity distribution was "M"-type distribution with electromagnetic stirring,the flow field has two circulating vortex.(2)The coalescence among inclusions in the bloom continuous caster with M-EMS occurs due to Brownian collisions,Stokes collisions,Archimedes collisions and turbulent collisions.Turbulent collisions are the most frequent,Archimedes collisions occupy the second place,Stokes collisions comes the third place,and Brownian collisions are negligible.(3)Archimedes force is introduced in the traditional inclusion population and mass conservation model.The inter-phase slipping velocity is three dimensional,and the collision source term should consider turbulent collision,Archimedes collision and Stokes collision.(4)The inclusion distribution is rotational symmetry and reflection symmetry at the free surface in the case of no M-EMS,but the inclusion distribution is rotational symmetry and but not reflection symmetry at the free surface in the case of M-EMS.(5)The inclusion number density and characteristic radius have a 'U' shape distribution in the continuous caster without M-EMS,but the inclusion concentration,number density and characteristic radius have a reverse 'U' shape distribution in the continuous caster with M-EMS.(6)With the increase of the distance from the free surface,the inclusion characteristic radius increases,but the inclusion concentration and number density decrease.