Numerical Simulation On Particle Motion Of Non-metallic Inclusions Under Electromagnetic Field

Numerical study has been conducted to investigate the effect ofelectromagnetic separation on non-metallic inclusions in metallic material.From the aspect of particle motion controlling, the inclusion separating effectwas simulated under combined magnetic field (CMF), which was generated bysynchronous application of a rotating magnetic field (RMF) and a downwardtraveling magnetic field (TMF). The mechanism and effect of separatingefficiency under different electromagnetic and container parameters wereinvestigated. From another aspect of particle agglomeration, three flow fieldbased methods accustomed to electromagnetic vibration have been developed toevaluate the aggregation behavior: the turbulence collision model, the highconcentration area method and the Monte-Carlo simulation.The CMF simulation showed that:(1) Electromagnetic force field and flowfield under CMF shared effect of rotating in horizontal direction as RMF andcircular symmetry pattern in the vertical direction as TMF. The flow field andthe Archimedes electromagnetic force were the two main factors responsible forparticle motion.(2) With the increase of electric frequency, the increasedmagnetic and force field driven the fluid motion and the inclusion eliminatingeffect was improved. With the increase of electric current, the magnetic andforce field distribution didn’t change except numerical scale changes andslightly enhance the separating effect. The force field was adjusted byelectromagnetic shielding, and the corresponding inclusion behavior was thendominated by fluid flied.(3) The bottom of the cylinder was changed into beveledge; the fluid was distributed along the curving wall and the particleconcentration diminished. In the Y-typed container, the force of the upper halfwas larger than the lower half, inducing a strong eddy vortex and lowconcentration region. With the increase of frequency, number of vortexincreased, the concentration differences of varied location became more obviouswhich is advantageous to the inclusion separation. Electromagnetic vibration simulation found that:(1) the electromagneticvibration can effectively promote the polymerization of silicon particles in themetal melt. Flow field was in an even disorder distribution; Turbulent collisionswas the main form of particle aggregation. When electric current or magneticfield increased, the flow field was intensified and enlarge the collisionprobability; the aggregation clusters size grew as the number of particles in eachclusters increased.(2) The inclusions in the flow field were easy to stay in thelow velocity zone and form a high concentration area; the particle collisionprobability in the area increased which promote aggregation. As cluster radiusincreased, clusters were distributed in random uniform order within the crosssection.(3) The collision polymerization is divided in two stages: thepolymerization and segregation process. As the fluid flux density increased, theagglomeration was restrained since the clusters were separated. As the interfaceenergy increased, the cluster became more compact at equilibrium state.The research indicates that: The CMF provided a better inclusion purifiedeffect than single magnetic field by controlling particle motion. Electromagneticvibration enhanced inclusions’ agglomeration behavior and facilitated the meltpurification. Both type of electromagnetic separating method provided a highlyefficient approach at eliminating inclusions.