水口底部形状对高拉速板坯连铸结晶器内钢液流股特征的影响  

Effect of nozzle bottom design on jet characteristics in continuous casting slab mold for high speed casting

作　　者：邓小旋[1] 王新华[1] 李林平[1] 杨叠[1] 季晨曦[2] 

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]首钢技术研究院,北京100041

出　　处：《炼钢》2014年第2期44-48,52,共6页Steelmaking

摘　　要：采用1︰1的连铸结晶器水模型,利用旋桨式流速仪与视频摄像的方法研究了5种不同水口底部形状(凸底、波浪底、凹底、平底与球底)的浸入式水口下流股的瞬态特征、回流区大小与对称性。结果表明:凸底和波浪底水口流股瞬态特征较稳定,而凹底、平底和球底水口的出口流股呈现出顺时针与逆时针交替旋转的特点。流股回流区的大小依次为:凸底>波浪底>凹底>平底>球底,工业初步试验结果表明:回流区过大是引起水口堵塞的原因之一。左右两侧流股的不对称性程度依次为:波浪底>凸底>凹底>平底>球底。水口底部形状对流股影响的机理分析表明:凸底和波浪底水口下的流股由于与水口底部作用很小,具有较大的动量和较小的湍动能,而球底水口下由于流股撞击底部会损失部分能量,导致其动量减小,但是却增加了其流动的紊乱程度(湍动能),使流股在出口处的速度分布更加均匀,进而减小了回流区的面积。A full scale water model was built to investigate the effect of bottom-design （mountain-, wave-, well-, flat- and round bottom） of submerged entry nozzles （SENs） on jet characteristics, backflow zone area and jet symmetry in continuous casting slab mold with propeller velocimeter and camera recording. The results show that the jet characteristic is stable for mountain- and wave-bottom SEN, however, shows a swirl flow for well-, flat- and round-bottom SEN with an alternative anticlockwise and clock- wise rotating. The order of backflow zone area （BFZ） is： mountain-bottom〉wave-bot- tom 〉well-bottom〉flat-bottom〉round bottom, plant trial results show that the large backflow zone is one cause for nozzle clogging. Furthermore, the order of jet velocity a- symmetry degree is similar to that order in high speed casting （steel throughput. 4. 48 t/min）. The spectrum powder analysis of jet velocity fluctuations show that the jet with mountain- and wave bottom SEN have less turbulence but more kinetic energy than any other SENs, which result in larger backflow zone. While round bottom SEN has much turbulent yet less kinetic energy jet, which result in smaller backflow zone.

关 键 词：高拉速 水模型 流股 结晶器 浸入式水口 

分 类 号：TF777.1[冶金工程—钢铁冶金]