板坯连铸结晶器电磁搅拌流场模拟

电磁搅拌对结晶器内流场和钢渣界面行为影响显著，通过建立1∶5的板坯连铸结晶器电磁搅拌物理模型试验系统和实际结晶器的数学模型，研究了不同搅拌电流对结晶器内流场的影响，并引入了自由表面冻结指数和卷渣指数分别评价自由表面钢液冻结和卷渣概率。结果表明，物理模拟试验系统测得的流场可为数值模拟提供验证支撑；当不施加电磁搅拌时，结晶器内流场为典型的双环流结构，自由表面流速较小，自由表面冻结指数为0.52,卷渣指数为0;施加电磁搅拌后，在结晶器上部形成水平环流，自由表面流速增大；增大搅拌电流，环流效果更加显著，自由表面冻结指数降低卷渣指数增大，当搅拌电流为700 A时，冻结指数降低至0.04,卷渣指数增加至0.245。因此，综合考虑卷渣指数和冻结指数可知，较优的搅拌电流为600 A。

Simulation of flow field in a slab continuous casting with in-mold electromagnetic stirring

Electromagnetic stirring has great effect on the flow field in the mold and the behavior of steel/slag interface, a physical model of slab mold with similarity ratio of 1∶5 and a mathematical model were built to investigate the effect of electromagnetic stirring (EMS) current on the flow field, the freezing index (R_f) and slag entrapment index (R_e) were introduced to evaluate the probability of meniscus freezing and slag entrapment, respectively. The results indicate that the flow field measured by physical model can be using as the validation for mathematical simulation. When EMS is not applied, the flow field within the mold is a classical double-roll structure, the flow velocity at free surface is relatively small, the freezing index and slag entrapment index are 0.52 and 0, respectively. The flow field changes significantly for the case with EMS, a horizonal recirculation flow has generated in the upper part of mold, the flow velocity at free surface increases. With the increase of EMS current, the recirculation flow enhances, the freezing index decreases while the slag entrapment index increases, as the EMS current increases to 700 A, the freezing index and slag entrapment index change to 0.04 and 0.245, respectively. Therefore, considering the slag entrapment index and meniscus freezing index, the optimizing stirring current is 600 A.