施加电磁搅拌的板坯连铸结晶器内流场数值模拟

Numerical simulation of the fluid field in slab continuous casting mold with electromagnetic stirring

电磁搅拌技术由于能够改善铸坯内部组织、提高铸坯质量、减少铸坯缺陷,在连铸中已经被广泛采用。该文基于Maxwell方程组和k-湍流模型,建立了电磁场作用下湍流流动的数学模型,来计算电磁搅拌板坯连铸结晶器内电磁场和金属流体自由面流动。结果表明:结晶器宽面边缘电磁力较大,在结晶器同一侧电磁力的切向分量方向大致一致,并且两侧方向相反。在结晶器内部,结晶器两侧每一对极之间的区域,电磁力呈现圆周状分布。在电磁搅拌的作用下,无电磁搅拌时典型的双环流流场结构发生改变,在水平方向上形成了水平的环流,从连铸工艺的角度来看,流场的这一改变有利于减小水口出口钢水射流对窄面坯壳的冲击,可提高表面质量。

Electromagnetic stirring technology has been widely used in continuous casting as it can improve the internal organization and quality and reduce the defect of the slab. Based on Maxwell equations and κ-ε turbulent mode, the mathematical model for the turbulent flow in the electromagnetic field is created to calculate the fluid flow in the slab continuous casting mold with electromagnetic stirring. The free surface flow of the metal liquid is calculated by VOF method. The numerical results show that the electromagnetic force on the wide face edge is large. On the Same side of the wide face edge the tangential component of the electromagnetic force is substantially the same. On the two wide face edges the direction of the electromagnetic force is opposite. Electromagnetic force is circumferentially distributed in the region between two magnetic poles on the wide face edges of the crystallizer. Dual circulation flow structure is changed by the electromagnetic stirring and a horizontal circulation is formed. The change of the flow field will reduce the impact of the jet flow of the metal liquid on the solidified shell on the narrow side of the crystallizer, and improve the surface quality.