两流中间包流场的物理模拟与结构优化

研究了坝、堰的结构和安装位置对55 t两流板坯连铸中间包内流体流动状态的影响,结合RTD曲线计算出的平均停留时间,确定了优化的中间包结构。研究表明:坝、堰组合之后可以改变流体的流动状态,延长流体运动的轨迹,提高流体的平均停留时间,但流体经过坝、堰后都存在一定体积的死区。采用坝1、堰1组合方案的中间包结构最佳,该方案的平均停留时间最长为299 s,死区体积分数最小为31.0%。优化控流参数后,在坝、堰间距为290 mm,堰到长水口间距为383 mm时,流体在中间包内的平均停留时间最长为351 s,死区体积分数最小为19.0%,比不加坝、堰的方案平均停留时间增加了65 s,死区体积分数减小了15.0%。由Newton公式计算表明,此优化方案的中间包去除夹杂物的临界直径为17.5μm,在351 s内夹杂物均能上浮去除。

Physical simulation of fluid field and structure optimization in two-strand tundish

The influence of the structure and location of dam and weir on fluid flow state in a two‐strand tundish is studied,and a set of optimal structure,combining with the average residence time calculated from RTD curve,is obtained.The result indicates that the fluid flow state can be changed and the path of the fluid flow can be prolonged as well as the average residence time is improved after using dam and weir.But there are some dead zones after fluid passed through the dam and weir.Combination scheme of No.one dam and weir is better than the others.Its average residence time is 299 s and the volume fraction of dead zone is 31.0%.After the optimization of flowing control parameters in tundish,the best case is that the distance between dam and weir is 290 mm and the distance between weir and the long nozzle is 383 mm.The longest average residence time is 351 s and the minimum volume fraction of dead zone is 19.0% under the above situation.Compared with that of no dam and weir,the average residence time increases by 65 s and the dead zone volume fraction decreases by 15.0%.Based on Newton formula,the calculated results show that the inclusions with diameter larger than 17.5 μm can float up within 351 s under this optimization situation.