浸入式水口对板坯结晶器卷入渣滴影响的物理模拟  

Physical simulation for effect of submerged entry nozzle on entrained slag droplet in slab mold

作　　者：彭笑萱 孙宇 段豪剑 陈威 张立峰 PENG Xiaoxuan;SUN Yu;DUAN Haojian;CHEN Wei;ZHANG Lifeng(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;School of Mechanical Engineering,Yanshan University,Qinhuangdao 066044,Hebei,China;School of Mechanical and Materials Engineering,North China University of Technology,Beijing 100144,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]燕山大学机械工程学院,河北秦皇岛066044 [3]北方工业大学机械与材料工程学院,北京100144

出　　处：《中国冶金》2023年第6期43-53,共11页China Metallurgy

基　　金：河北省自然科学基金资助项目(E2021203222);国家自然科学基金资助项目(U22A20171,52104343)。

摘　　要：结晶器卷渣是导致连铸坯表面产生缺陷的主要原因。结晶器内钢液的流动状态与卷渣的发生及卷入渣滴的运动行为有着密切联系,而结晶器浸入式水口的结构对钢液流动有直接影响。因此,研究浸入式水口对结晶器内流体流动及卷渣现象的影响有着重要意义。通过建立相似比为1∶2的板坯结晶器水模型,系统研究了浸入式水口内径、出口角度、水口底部形状和浸入深度等对结晶器卷渣的影响。采用高速摄像机和PIV测速仪对结晶器内弯月面卷渣行为及流场分布进行了测量,同时通过图像后处理软件对数据进行了可视化分析,确定了不同工况条件下发生卷渣的临界拉速,定量统计了不同水口参数和不同吹气流量下卷入渣滴直径的变化。结果表明,卷入渣滴的运动轨迹与结晶器内流场流态存在关联。在一定范围内,采取增加水口内径、增大水口出口角度、增大水口浸入深度、采用凹底型水口等措施可降低结晶器卷渣概率,并且减小卷入渣滴直径,缩短渣滴重新上浮至渣层的时间。本研究可为优化连铸工艺参数提供技术指导。The slag entrainment in mold is the main cause of surface defects of slab.The flow field inside mold is closely related to the occur of slag entrainment and the behavior of entrained slag droplet.The structure of submerged entry nozzle(SEN)has direct effect on the flow of molten steel.Therefore,it is of great significance to study the influence of SEN on fluid flow and slag entrainment in the mold.A water model with 1:2 scale of slab continuous casting mold was established to systematically study the effect of inner diameter,outlet angle,bottom shape and immersion depth of submerged entry nozzle on the slag entrainment.The slag entrainment behavior at the meniscus and the distribution of fluid field were measured using the charged coupling devices camera(CCD camera)and the particle image velocimetry(PIV).At the same time,the data were analyzed visually using image post-processing software.The critical casting speed of slag entrainment under different working conditions was determined,and the diameter variation of entrained slag droplets with different SEN parameters and different gas flow rates were quantified.The results show that the trajectory of entrained slag droplet is related to the flow field in the mold.In a certain range,increasing the SEN inner diameter,increasing the SEN outlet angle,increasing the SEN immersion depth and adopting the concave bottom of SEN can reduce the probability of slag entrainment in mold,reduce the diameter of entrained slag droplets,and shorten the time for droplet floating up to the slag layer.This study could provide technical guidance for optimizing the process parameters of continuous casting.

关 键 词：结晶器卷渣 渣滴直径 浸入式水口结构 粒子图像测速 水模型 

分 类 号：TF777[冶金工程—钢铁冶金]