电磁搅拌条件下结晶器内钢液多相流动和卷渣现象的大涡模拟  

Large eddy simulation on the multiphase fluid flow and slag entrainment in a continuous casting mold with electromagnetic stirring

作　　者：李琪蓝 张立峰 陈威 王亚栋 赵震 张静[4] LI Qi-lan;ZHANG Li-feng;CHEN Wei;WANG Ya-dong;ZHAO Zhen;ZHANG Jing(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;School of Mechanical and Materials Engineering,North China University of Technology,Beijing 100144,China;School of Mechanical Engineering,Yanshan University,Qinhuangdao 066004,China;School of Vehicle and Energy,Yanshan University,Qinhuangdao 066004,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]北方工业大学机械与材料工程学院,北京100144 [3]燕山大学机械工程学院,秦皇岛066004 [4]燕山大学车辆与能源学院,秦皇岛066004

出　　处：《工程科学学报》2022年第4期690-702,共13页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(E2021203222);河北省省级科技计划资助项目(20591001D)。

摘　　要：针对大方坯连铸结晶器内的流动和卷渣行为进行了三维数值模拟仿真,应用大涡模拟模型模拟湍流、应用VOF模型模拟渣相‒钢液和空气‒渣相‒钢液的多相流.研究对比了钢液单相流动、渣相‒钢液两相流动和空气‒渣相‒钢液三相流动3种模型下结晶器内的流动、钢‒渣界面液位形状和波动及卷渣行为,并通过工业用计算机断层成像技术(工业CT)检测了连铸坯中大颗粒卷渣类夹杂物数量随着电磁搅拌电流强度的变化.结果表明,在150 A、2 Hz结晶器电磁搅拌下,3种模型得到的结晶器内钢液流场差别较小,但在钢‒渣界面处差别较大.钢液单相模型下钢液表面流动速度比其他两种模型钢‒渣界面处的速度更大.渣相‒钢液两相模型和空气‒渣相‒钢液三相模型的卷渣速率分别为0.00118和0.00040 kg∙s^(−1).渣相‒钢液两相模型条件下,由于上表面即渣的顶面不能弯曲,所以钢‒渣界面处的湍动能没有得到耗散,所以比三相模型的湍动能更大,因此其预测的卷渣速率偏大.当搅拌电流强度增大到300 A,渣相‒钢液两相模型和空气‒渣相‒钢液三相模型的卷渣速率分别为150 A条件下的5倍和15倍;当电流频率增大到4 Hz,渣相‒钢液两相模型的卷渣速率变化很小,空气‒渣相‒钢液三相模型的卷渣速率降低为2 Hz条件下的1/3.因此,为了正确的模拟和预测结晶器钢‒渣界面处的卷渣行为,必须使用空气‒渣相‒钢液三相瞬态模型进行模拟仿真.Due to the closed environment with high temperature and pressure in the continuous casting(CC)process,numerical simulation technology with flexible control and low cost of phenomena in the CC mold has been a research hotspot.The multiphase flow,heat transfer,solidification of steel and slag,and other complex interaction in the mold are some of the simulation difficulties.Various physical models have been established in recent studies to obtain the reactions and effects of the different phases.However,the influence of different models on the simulation results is rarely studied.In the current study,a three-dimensional(3D)mathematical model,coupled with the large eddy simulation(LES)turbulent model and volume of fluid(VOF)multiphase model,was established to investigate the multiphase flow,slag-steel interface level fluctuation,and slag entrainment in the mold of a steel bloom CC with mold electromagnetic stirring(M-EMS).The air‒slag‒steel three-phase flow,slag‒steel two-phase flow,and steel single-phase flow were compared.An industrial computerized tomography(CT)was used to detect the large entrainment slag inclusions in blooms with different stirring current intensities.With a 150-A current intensity and a 2-Hz frequency electromagnetic stirring at the mold,the multiphase flows are approximately identical for the three models,although different at the slag‒steel interface.The speed on the top surface of the single-phase model is higher than that of the multiphase models.The level fluctuation of the two-phase model is slightly more severe than that of the three-phase model,and the net slag entrainment rates of the two-phase and three-phase models are 0.00118 and 0.00040 kg·s^(−1),respectively.The turbulence kinetic energy at the slag‒steel interface of the two-phase model is significantly greater than that of the three-phase model because the turbulence kinetic energy can not be dissipated,unlike that in the actual process.Thus,the predicated slag entrainment obtained by the two-phase model is higher.O

关 键 词：多相流 卷渣 电磁搅拌 大涡模拟 方坯结晶器 

分 类 号：TG142.71[一般工业技术—材料科学与工程]