Numerical Simulation Of Multiphase Interaction In Continuous Casting Mold Based On Euler-Lagrange Method

Argon bubbles are often injected into molten steel in mold to prevent nozzle clogging and to promote removal of inclusions during steel continuous casting.Entrapments of bubbles in solidifying front cause defects in steel products,which is even worse when the inclusion is attached to bubbles.The coalescence and breakup of argon bubbles will change their size and spatial distribution,and then affect the entrapments of bubbles.However,those mechanisms are often simplified in the previous studies,therefore it is hard to obtain the size and spatial distribution of bubbles precisely.To examine the interaction and removal of discrete bubbles and inclusions in molten steel and to reduce defects in steel products,a detailed numerical model,considering transport and capture of discrete bubbles and inclusions,coalescence and breakup of bubbles and bubble-inclusion entrapment,is developed.Previous multiphase flow models did not take all these factors into account.In addition,the interaction between bubbles and inclusions is simplified in traditional research,assuming that the absorbed inclusions are removed.In fact,the bubbles may carry inclusions to the solidifying front,resulting in defects.In this study,the subsequent movement and behavior of inclusions were tracked after adhering.The inclusion removal rates in continuous casting mold at different initial bubble diameters and inclusion diameters were predicted.Larger inclusions have a higher removal rate.And the predicted removal rates ranging from 14%to 30%agree well with industrial experiment measurements.It is also found that smaller bubbles have a higher capacity to remove inclusions and very small bubbles may cause more defects when they are attached by inclusions and entrapped by solidifying front.Under the conditions of this study,the optimum initial bubble size is 1.0 mm.Results show that this developed model can reasonably predict the behaviors of bubbles and inclusions and their interactions in molten steel.Such a model should be useful for the optimization of practical operation in continuous steel casting.Meanwhile,it can also be used as a general three-phase flow simulation model in related fields.