连铸中间包底吹氩物理模拟和工业实践

通过实验室物理模拟和工业应用实践,研究了透气砖底吹氩对本钢中间包内流体流动行为和去除钢中夹杂物行为的影响.物理模拟研究结果表明,底吹氩可以显著改善中间包内钢水的流动特征,延长钢水在中间包内的停留时间,提高中间包内钢水的混合程度,减少死区体积分率;吹气位置越靠近中间包水口侧对流体特征参数的改变效果更佳;吹氩形成的微气泡群可以显著改善中间包内流体的运动轨迹,流体运动的路线更加曲折,并且全程流动靠近液体表面.工业实践表明,底吹氩形成的“气幕挡墙”对夹杂物效果去除效果明显,与不吹氩相比,铸坯中夹杂物指数从7.33～8.98 mg/（10 kg）降低至4.21～4.33 mg/（10 kg）,且大颗粒夹杂物数量明显减少,没有发现尺寸大于30～50μm的夹杂物.     

湍流控制器形状对中间包内流体流动的影响

通过水模实验,以平均停留时间、活塞区体积特征时间为衡量标准,研究不同形状的湍流控制器在不同挡墙与导流孔的组合下对中间包内流体流动的影响,得出无挡墙、直挡墙、U挡墙和弧挡墙下湍流控制器与挡墙导流孔的优化组合,优化中间包内流体流动。     

板坯连铸中间包结构的优化

对鞍钢三炼钢板坯连铸中间包结构进行了优化研究,发现原中间包结构造成钢水在中间包的最小停留时间短和活塞流体积小,死区体积大,不利于钢水中的非金属夹杂物上浮.采用合理结构的挡墙和湍流控制装置能够明显改善中间包内流体的流动特性,可以使钢包长水口注流区上方的液面流动平稳,促进钢水中的非金属夹杂物上浮,提高铸坯质量.     

六机六流中间包挡墙设计水模试验

在中间包内设置"U"形挡墙,调整挡墙上导流孔的位置、方向及大小,用自来水模拟钢水进行水模试验,改善中间包内流体的流动状况。通过不断试验,中间包内的流场得到优化,各流示踪剂响应时间均在44s附近,平均停留时间为651s,死区体积百分比为15%,照片上流体的流动状况也比较合理。     

重钢5流方坯连铸中间包控流装置的数理研究

对重钢24t中间包控流装置进行水力学模型试验和数值模拟,通过测定停留时间分布(RTD)曲线和夹杂物的排除量,研究了不同尺寸湍流控制器对中间包流体流动特性的影响。研究结果表明,使用合适的湍流控制器和现有挡墙设置组合,可以延长水口响应时间及平均停留时间,提高活塞流区体积分数30%及降低死区体积分数50%,中间包内流体流动特性得到改善。     

薄板坯连铸中间包吹氩行为的物理模拟

中间包吹氩是适应洁净钢冶炼的新技术、新方法。依据相似原理,在实验室建立了一定相似比的薄板坯连铸中间包物理模型。比较了传统堰坝组合,吹氩气幕挡墙分别代替堰、坝对中间包流体流动特征的影响,并尝试在中间包内采用双气幕挡墙的控流方式。结果表明,气幕挡墙分别代替堰、坝,中间包停留时间和死区体积与堰 坝组合十分相近;双气幕挡墙代替堰 坝组合,除死区体积较大外,停留时间接近堰 坝组合。上述结论为气幕挡墙技术的进一步应用提供了参考依据。     

控流装置对板坯中间包流场优化的影响

根据相似原理,用1:3水模型研究了230 mm×130 mm板坯连铸用60 t中间包内钢水的流动特征,通过测定模型中间包内停留时间分布曲线,计算其平均停留时间及死区,活塞区和混合区的体积。结果表明,采用下挡墙开孔能有效地改善中间包内流场,得出优化后合适的钢包控流装置组合为开孔下挡墙+湍流控制器,下挡墙高133 mm,距离冲击区765 mm。优化后的中间包比原中间包平均停留时间增加了24 s,死区体积由原来的14.8%下降至6.7%。     

二流T型23 t中间包控流装置的数值模拟和结构优化

通过计算流体力学软件FLUENT建立的数学模型对钢厂200 mm×1 600 mm铸坯二流T型23 t中间包现挡墙和坝、湍流控制器和坝、湍流控制器和现挡墙以及新挡墙4种结构方案进行三维数值模拟,研究原中间包及安装不同控流装置后的钢水流动特性。结果表明,在所有的设计方案中安装有湍流控制器和坝的中间包能够达到最佳优化效果;中间包的死区体积分率由30.18%降到16.51%,活塞流区与死区的体积分率比R_Vp/Vd由55.80%增大到129.44%;中间包内流动稳定,有利于夹杂物的上浮。     

八流连铸中间包控流装置优化的水力学模拟

通过几何相似比1:3.5的水模型实验对40 t八流中间包不同控流装置下的流场进行了模拟研究。结果表明,原中间包平均滞止时间短,一侧4个水口的停留时间相差较大;优化的双导流孔挡墙可使中间包死区体积分数比原型减少19.15%,优化的C12W1矩形挡墙可使中间包死区体积分数比原型减少31.49%;中间包一侧4个水口的滞止时间差值减少;设置湍流抑制器虽然增加钢液的滞止时间和峰值时间,但不能有效地降低死区体积分数。     

两流非对称中间包内控流装置优化的水模型研究

通过水模型实验和数值模拟,研究了两流非对称中间包采用不同控流装置时流体流动的特性.结果表明:圆形湍流控制器与单挡墙组成的控流装置中间包两出口流体流动差异较大;非对称长方形湍流控制器和多孔挡墙组成控流装置的中间包,两流之间的平均停留时间差异是圆形湍流控制器和单挡墙组成控流装置中间包的2/3,且近长水口侧出口的平均停留时间...     

40t单流中间包控流装置的优化配置

采用水模型和工业验证的方法针对40 t单流中间包的控流装置进行优化配置研究.通过对单独湍流抑制器控流装置、湍流抑制器+下挡墙组合控流装置、湍流抑制器+下挡墙+上挡墙组合控流装置的研究表明,下挡墙在改善钢液流动形态和减少中间包内死区方面所起的作用大于上挡墙.平均停留时间随下挡墙与长水口的距离增加呈先增大后减小的趋势.确定了单流中间包以湍流抑制器+下挡墙的优化组合形式,死区比例由原来的25.9%降低到了13.6%.通过系统取样分析发现优化后中间包内T.O和N含量大幅降低,正常坯中的大型夹杂物质量分数也由原来的8.4×10-7降低到3.2×10-7.      

气幕挡墙中间包钢水流动的数值模拟

根据二流连铸1500mm×250mm板坯时中间包的操作工艺参数,采用欧拉两流体模型,多孔介 质模型和拉格朗日随机轨道模型,模拟计算了采用湍流控制器和气幕挡墙技术的中间包内钢液流动特性和 夹杂物的运动轨迹,并用Monte-Carlo法统计了夹杂物的总去除率。模拟结果表明,采用中间包气幕挡墙技术 可以有效改善钢液的流动特性,延长钢液停留时间,减小死区体积;当吹气量为0.90m³/h时,夹杂物去除率比 不吹气工艺增加15.6%     

Flow Control in Six-Strand Billet Continuous Casting Tundish With Different Configurations

A 1∶2.5 scale tundish model was set up in laboratory for a six-strand billet continuous casting tundish with different configurations to investigate fluid flow characteristics under different operational conditions by measuring residence time distribution curves.It was found that minimum residence time,maximum concentration time and average residence time of the three strands on the same side of the tundish with the former configuration under normal operation,that is,six strands were open,were small and non-uniform and the tundish had large dead volume fraction.Vortexes easily formed on the liquid surface in the pouring zone of the tundish.The fluid flow characteristics in the tundish with the optimal turbulence inhibitor and baffles were improved and became less non-uniform among the strands.Vortexes were not found on the pouring zone surface in the optimal tundish.For non-normal operation,that is,one strand was close,it was important to choose which strand to be closed for maintaining flow characteristics of the rest two strands.It was found from this investigation that fluid flow characteristics in the optimal configuration tundish with closing strand 2 were better than those with closing strand 3 on the same side.     

连铸中间包湍流控制器水模实验研究

通过水模实验，研究了湍流控制器对连铸中间包流体流动的影响。合理结构的湍流控制器能够改善中间包流体流动特性，最小停留时间增加，活塞流体积提高，死区体积下降。实验观察发现，中间包采用湍流控制器后，在两块上渣堰之间的液面流动平稳，可以减少卷渣现象。     

Flow Control in Six-Straud Billet Continuous Casting Tundish With Different Configurations

 A 1:2.5 scale tundish model was set up in laboratory for a six-strand billet continuous casting tundish with different configurations to investigate fluid flowing characteristics under different operational conditions by measuring residence time distribution curves. It was known from the investigation that minimum residence time, maximum concentration time and average residence time of the three strands in the same side of the tundish with the former configuration under normal operation, that is, 6 strands were open, were small and non-uniform and the tundish had large dead volume fraction. Vortexes easily formed on the liquid surface in the pouring zone of the tundish. The fluid flow characteristics in the tundish with the optimal turbulence inhibitor and baffles were improved and became less non-uniform among the strands. Vortexes were not found on the pouring zone surface in the optimal tundish. Under un-normal operation, that is, one strand was close, it was important to choose which strand should be closed for flowing characteristics of the rest two strands. It was found from this investigation that fluid flowing characteristics in the optimal configuration tundish with closing strand 2 were better than those with closing strand 3 at the same side.     

板坯连铸中间包结构优化的研究

结合某公司双冲击点板坯中间包生产现状,利用水模实验对中间包内钢水流动特性进行了研究.结果表明:原中间包结构存在明显的短路流,钢水停留时间偏短,死区体积分率偏高,不利于夹杂物上浮去除.同时,由于在高度较大的两湍流控制器间钢水不能流出,影响金属收得率.这种具有双冲击点的中间包,应按照对称的两个单流板坯中间包进行结构优化.采...     

中间包底吹氩行为的数值模拟

 根据某钢厂连铸中间包的实际操作参数,采用欧拉两相流模型,气体入口边界条件按照多孔介质进行处理,利用CFX软件模拟计算了底吹氩中间包内钢液的流场。结果表明:底吹氩气技术代替上挡墙或下挡墙2种情况下,注入区钢液混合加剧,有利于夹杂物碰撞长大。浇注区靠近液面处速度提高易引起卷渣。当采用湍流控制器、上挡墙、下挡墙、底吹氩技术时,吹氩位置对钢液流动的影响较大,当在湍流控制器和上挡墙之间吹入气体时,钢液的流动特性有利于夹杂物的上浮去除。     

Water Modelling Experiments of Argon Bubbling Curtain in a Slab Continuous Casting Tundish

Fluid flow characteristics in a two‐strand slab tundish with Ar bubbling curtain were studied in water modelling experiments. It was found that the Ar bubbling curtain can greatly improve the flow characteristics in the tundish with a weir, a dam and a turbulence inhibitor. It dramatically increased the peak concentration time and plug volume and greatly decreased the dead volume, but hardly influenced the minimum residence time. Therefore, the fluid flow characteristics in a tundish with Ar bubbling curtain were favourable to the flotation and separation of inclusions from molten steel. The flow characteristics with low gas flow rate and short distance of the Ar bubbling curtain from the tundish outlet were better than those with high gas flow rate and large distance of the curtain from the outlet.