中间包上水口区域塞棒吹氩气泡运动行为研究
Study on motion behavior of bubbles in argon blowing through a tundish stopper rod
-
摘要: 塞棒吹氩技术是连铸过程中防止水口堵塞和提高钢液质量的重要手段,为优化连铸中间包塞棒吹氩工艺,本文以某厂中间包为原型,建立了1∶1水-氩气物理模型并结合数值模拟,系统研究了塞棒吹氩孔位置、拉速、吹氩量及塞棒开度对氩气泡运动行为、流场和湍动能分布的影响规律。研究表明:位于塞棒头密封面上方的B1位置效果最优,其气流能有效冲刷密封面,在吹氩量为3 L/min且拉速为1.3、1.5、1.7 m/min工况下,塞棒开度在达到33.75、36.80、41.90 mm时仍能保证气泡全部进入水口;拉速对气泡运动影响显著,在开度为30 mm、吹氩量为3 L/min的条件下,拉速从1.3 m/min增大至1.7 m/min,气泡平均直径由12.5 mm增大至15.1 mm,流经区域平均宽度由51.9 mm缩减至42.7 mm;吹氩量增加会同时提升气泡的体积和在水口内运动范围,当吹氩量由5 L/min减少至1.8 L/min时,平均气泡直径由18.1 mm减少至12.4 mm,气泡流经区域平均宽度由47.8 mm减少至32.7 mm;B1位置适用塞棒开度上限约为40 mm,开度越低吹氩效果越好,开度超过50 mm则导致气流合并甚至上浮,失去冲刷塞棒头的作用并增加塞棒在中间包钢液面受侵蚀的风险。Abstract: Argon blowing through the stopper rod is a key technique in the continuous casting process for preventing nozzle clogging and improving molten steel quality. To optimize the stopper rod argon blowing process in continuous casting tundishes this study establishes a 1∶1 water-argon physical model based on a prototype tundish from a specific plant and combines it with numerical simulation. The study systematically investigates the influence of argon blowing hole position casting speed argon flow rate and stopper rod opening on argon bubble behavior flow field and turbulent kinetic energy distribution.The results indicate that the B1 position located above the sealing face of the stopper rod head yields optimal performance as its gas flow can effectively scour the sealing face. At an argon flow rate of 3 L/min bubbles are able to fully enter the nozzle at specific stopper rod openings corresponding to different casting speeds: specifically 33.75 mm at 1.3 m/min, 36.80 mm at 1.5 m/min and 41.90 mm at 1.7 m/min.Casting speed has a significant effect on bubble motion. For instance at a 30 mm opening and a 3 L/min argon flow rate increasing the casting speed from 1.3 m/min to 1.7 m/min increases the average bubble diameter from 12.5 mm to 15.1 mm. Conversely this speed increase reduces the average flow area width from 51.9 mm to 42.7 mm. Adjusting the argon flow rate simultaneously alters bubble volume and their range of motion within the nozzle. When the argon flow rate is reduced from 5 L/min to 1.8 L/min, the average bubble diameter decreases from 18.1 mm to 12.4 mm. Consequently the average bubble flow area width narrows sharply from 47.8 mm to 32.7 mm.The B1 position is suitable for a stopper rod opening up to approximately 40 mm with smaller openings generally resulting in better blowing effectiveness. However if the opening exceeds 50 mm the gas streams merge or float upward. This behavior not only loses the scouring effect on the stopper rod head but also increases the risk of erosion to the stopper rod at the molten steel surface in the tundish.
下载: