钢包底吹氩精炼混匀判据及合金加入位置研究

Study of mixing criterion and alloy adding position during bottom argon blowing refining process

在钢包底吹氩水模型试验中,传统混匀判据是通过在钢包模型中安装1~2个电导探头监测示踪剂浓度变化,从而判断混匀程度。由于钢包各处混匀时间差异较大,加之监测点位置选择的主观性,易造成混匀时间测量不准。针对该问题,通过数值计算的研究方法模拟了钢液的流动与混匀过程。计算结果表明：随着钢液混匀程度的增加,钢液中整体示踪剂浓度标准差降低,当整体示踪剂浓度标准差在约0.02以下时,钢包混匀程度已达到100%,基于此提出在水模型试验中测量混匀时间时,可以在钢包中3个不同高度处各安装3个电导探头监测示踪剂浓度变化,当这9处监测点示踪剂浓度标准差小于0.02时,即可认为达到混匀。研究了不同示踪剂加入位置下的混匀时间,结果表明,在钢包一侧距离钢包中心约1/6R处加入示踪剂时,混匀时间最短为77.5s,该位置为理想的合金加入位置。而在靠近气液两相区的钢包液面边缘处加入示踪剂时,混匀时间最长为137.3s,在该位置加入合金则不利于钢液的快速混匀。

In the hydraulic model experiments of bottom argon blowing refining process,the traditional mixing criterion was determining the mixing degree by monitoring the tracer concentration with the help of one or two conductivity electrodes which were set in the ladle model.Due to the difference between the local mixing time at different positions and the randomness in the choice of monitoring positions,the measured mixing time may not be realistic.In regard to this,the fluid flow and mixing process were simulated by numerical calculation.The result showed that with the increase of mixing degree,the standard deviation of tracer concentration decreased.When the standard deviation was lower than 0.02,the mixing degree was 100 %.Based on this,it was raised that 9conductivity electrodes should be set at three sections which were distributed alone the height.When the standard deviation of tracer concentration was lower than 0.02,the concentration could be believed to be uniform.The effect of adding position on mixing time was also studied in this paper.The result showed that the mixing time was about 77.5swhen the tracer was added from the position which was located at a distance about 1/6radius from the center.When the tracer was added from the edge which was close to the plume,the mixing time was about 137.3s.The former position was the ideal alloy adding position.