电磁精炼钢包内气泡行为与均混时间的模拟分析

Simulation analysis of bubble behavior and mixing time in electromagnetic refining ladle

对150 t LF钢包采用欧拉-拉格朗日方法进行数值建模,采用受气泡形状影响的Kuo曳力模型,考虑静压对气泡粒径的影响,研究了在钢包底部中心吹氩,R/2处施加旋转电磁搅拌时钢包内气泡的运动行为与合金混匀效果。结果表明:施加底部偏心电磁搅拌可以有效改变气泡分布状态,在0~400 A范围内,电流强度越大,气泡偏移程度越大,且气泡弥散程度也越大。施加底部偏心电磁搅拌后,1 mm小气泡平均停留时间可延长至4.38 s,20、30、40 mm等大气泡停留时间也均可延长60%左右。施加底部偏心电磁搅拌,当电流强度为400 A即可有效改善钢包内底部钢液温度较低、四周温度较高的分布问题。电流强度增大至400 A,相比未施加电磁搅拌,合金扩散效率增强了60.4%,钢液混匀时间可缩短145 s。

The Euler-Lagrange method was used for numerical modeling of the 150t LF ladle,and the Kuo drag force model affected by the bubble shape was used.This method considered the influence of static pressure on bubble size.The argon inlet was at the bottom of the ladle and a rotating electromagnetic stirrer was at R/2 at the bottom of the ladle.The bubble behavior and the mixing time of the alloy were investigated.The results show that the electromagnetic stirrer placed eccentrically at the bottom can effectively change the bubble distribution state.In the range of 0-400 A,the greater the current intensity of the electromagnetic stirrer,the greater the degree of bubble deviation and the greater the degree of bubble dispersion.After applying the eccentric electromagnetic stirring at the bottom,the average residence time of 1 mm bubbles can be extended to 4.38 s,and the residence time of large bubbles such as 20 mm,30 mm and 40 mm can also be extended by about 60%.When the current intensity is 400 A,this electromagnetic stirrer can effectively improve the problem of lower temperature of molten steel at the bottom of the ladle and higher temperature around the center.When the current increases to 400 A,the alloy diffusion efficiency is increased by 60.4%,and the mixing time of molten steel can be shortened by 145 s.