Effect of nozzle position on flow field and solidification in billet mold
Owing to the loss of symmetry in the flow field of the inner and outer arcs when the curved continuous casting nozzle is centered,as well as the uneven temperature of the inner and outer arcs during the production,the solidification quality of the continuous casting billet is seriously affected.Studying the effect of nozzle positioning on improving flow field distribution is particularly crucial.In this study,the mathematical model of electromagnetic,flow,heat transfer and solidification coupling of steel in arc mold is established.The influence of SEN offset direc-tion and offset distance on the flow behavior is studied,and the symmetry index Is is introduced to evaluate the uni-formity of solidified shell.It is found that the SEN offset to inner arc increases the flow field difference and produces the bias flow phenomenon,and the application of electromagnetic stirring exacerbates this phenomenon.When the SEN is offset to the outer arc,regardless of whether electromagnetic stirring is applied or not,the index of Is in-creases and then decreases of each plane,improving the flow field distribution in the mold and make it tend to be symmetrical,which is beneficial to improve the quality of the casting billet.When M-EMS is applied,the vortex core gradually moves to the center of the electromagnetic stirring center surface with the distance of SEN offset to the outer arc increase.Although the steel flow is not symmetrical in the form of inner and outer arcs,there is a cer-tain deflection angle,which increases the temperature difference between the inner and outer arcs in all case models.However,for M-case 6,the temperature difference increases is only 1.666 ℃.When the SEN is offset to the outer arc by 6.5 mm,the index of Is and the uniformity of the solidified shell are the highest,the velocities of the inner and outer arc almost coincide,the temperature difference between the inner and outer arcs is the smallest,the distri-bution of the steel flow field is the best.By adjusting the position of the SEN,the symmetry of the flow field in the mold can be improved,the uniformity of the solidified shell can be enhanced,and the bias flow phenomenon caused by the mold curvature and the electromagnetic stirring intensification can be eliminated.
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