吹氩板坯倒角结晶器气液两相流动Euler-Lagrange双向耦合模拟

Euler-Lagrange two-way method numerical simulation on gas-liquid two-phase flow of continuous casting slab chamfered mould with argon blowing

为研究断面尺寸为1 490 mm×230 mm的吹氩板坯倒角结晶器内不同拉速对连铸生产过程中气液流动状态的影响,采用Euler-Lagrange方法建立了氩气-钢液两相流动双向耦合数学模型,并根据相似原理建立了吹氩板坯倒角结晶器1∶1水模型,通过对比物理模拟与数值模拟气泡分布结果验证了模型的准确性。随着拉速由0.6 m/min增大至1.8 m/min,上涡心高度下移89 mm,下涡心高度下移528 mm,氩气泡上浮对流股的抬升作用明显减弱,流场形态逐渐趋近于未吹氩时的板坯典型双环流形态;拉速增大使气泡分布范围扩大,气泡运动轨迹与水平方向的夹角增大;拉速增大能够有效减弱氩气泡在水口附近集中上浮引起的水口周围液位高度升高,同时上环流动能增强使得窄面与倒角面附近液位升高,液位最大高度差相较低拉速时明显下降;拉速增大使倒角面附近的液面流速显著提高,倒角面附近最高流速由拉速0.6 m/min时的0.007 m/s提高至拉速1.8 m/min时的0.057 m/s。

In order to study the influence of different casting speeds on the gas-liquid flow state in the slab chamfered mold of argon blowing with a section size of 1 490 mm × 230 mm during continuous casting process, a two-way coupling mathematical model of argon gas-molten steel two-phase flow was established by Euler-Lagrange method, and a full scale water model of the slab chamfered mold with argon blowing was established according to the similarity principle, the accuracy of the model is verified by comparing the results of physical simulation and numerical simulation of bubble distribution. With the increase of casting speed from 0.6 m/min to 1.8 m/min, the height of upper vortex center decreases 89 mm, and the height of lower vortex center decreases 528 mm, the uplifting effect of argon bubble on stream is obviously weakened, and the flow field gradually approaches the typical double-roll flow pattern of slab without argon blowing. With the increase of casting speed, the bubble distribution range is enlarged, the included angle between the bubble movement track and the horizontal direction is increased. With the increase of casting speed, the rise of liquid level around the SEN caused by the argon bubbles rise near the SEN can be effectively weakened, meanwhile, the kinetic energy of the upper loop flow increases, making the liquid level near the narrow surface and the chamfered surface rise, and the maximum height difference of the liquid level decreases obviously compared with that at the low drawing speed. The increase of casting speed significantly increases the liquid surface velocity near the chamfered surface, and the maximum velocity near the chamfered surface increases from 0.007 m/s at the casting speed of 0.6 m/min to 0.057 m/s at the casting speed of 1.8 m/min.