钢包浇注过程中自由表面旋涡流动行为的物理模拟研究

Physical Modeling on Behavior of Free Surface Vortex Flow in Ladle during Teeming Process

连铸钢包浇注末期出现的旋涡卷渣现象对连铸钢水质量产生了重要的影响,为了有效控制生产中的旋涡卷渣现象,有必要对钢包浇注末期旋涡的产生机理开展详细研究。依据相似原理,构建了相似比为1:6的钢包物理模型,对钢包浇注过程中旋涡产生及卷渣过程进行研究,研究了初始液面高度、出水口尺寸与布置位置、出水口结构等因素对旋涡形成规律的影响。经研究得知:旋涡形成过程与初始液面高度无关;钢包出水口尺寸和布置位置对于旋涡形成过程影响显著。当偏心率小于1,2时,随着出水口直径的增大,旋涡临界高度逐渐降低;反之,当偏心率大于1/2时,随着出口直径增加,临界起旋高度增加。对于同一尺寸出口而言,随着偏心率的增加,旋涡临界高度逐渐降低,而且当偏心率大于1/2后临界高度显著降低。通过改变出水口内部结构可以有效降低旋涡临界高度。提出的三片挡块式出水口结构,可以显著降低钢包浇注末期的旋涡临界高度,降低高度达50%左右。

Cleanness of molten steel in tundish is closely related to the slag entrapment by vortex at end of ladle teeming process. The formation mechanism of the vortex was investigated in order to develop effective measurement to prevent its negative effect. Based on the similarity criteria, series water modeling experiments, whose scale was 1：6, have been carried out to investigate the formation and evolution mechanisms of vortex in ladle during teeming process. It came to the conclusions as follow. Under the present experimental conditions, the vortex formation has less relationship with the initial level of fluid in ladle. Nevertheless, the exit diameter and location played important role for vortex evolution. The critical height of vortex formation decreased with increasing of exit diameter when exit eccentricitye was less than 1/2. On the contrary, the critical height of vortex formation increased with increasing of exit diameter when exit eccentricitye was greater than 1/2. The critical height decreased with increasing of exit eccentricity for the same exit, the best value of that was greater than 1/2. The authors developed a new exit structure, which dramatically delayed the formation of vortex at the end of teeming process.