Optimization of lfow control devices in a ten-strand billet caster tundish

The physical model of a ten-strand bilet caster tundish was established to study the effects of various lfow control devices on the melt lfow. Before and after the optimization of the melt lfow, the inclusion removal in the tundish was evaluated by plant trials. The physical modeling results show that when combined with a baflfe, the turbulence inhibitor, instead of the impact pad, can signiifcantly improve the melt lfow. A turbulence inhibitor with a longer length of inner cavity and without an extending lip at the top of the sidewal seems to be efifcient in the improvement of the melt lfow. Various types and designs of baflfes al inlfuence the lfow characteristics signiifcantly. The “V” type baflfes are better than the straight baflfes for lfow control. The “V” type baflfe with four inclined holes at the sidewal away from the stopper rods is better in melt lfow control than the one with one inclined hole at each sidewal. The combination of a wel-designed turbulence inhibitor and an appropriate baflfe shows high efifciency on improving the melt lfow and an optimal proposal was presented. Plant trials indicate that, compared with the original tundish conifguration in prototype, the inclusions reduce by 42% and the inclusion distribution of individual strands is more similar with the optimal one. The optimal tundish conifguration effectively improves the melt lfow in the ten-strand bilet caster tundish.     

小方坯连铸中间包流场数值模拟与分析

为了研究不同形状湍流抑制器及不同种类开孔挡墙对中间包流场流动特性及温度分布均一性的影响,以10流小方坯连铸对称双中间包为研究对象,通过Fluent软件对单边5流中间包流场进行数值模拟分析。研究结果表明,湍流抑制器可有效降低注流区湍流的产生,且中间包挡墙的形状和开孔的调整对浇注区各流出口流场及温度场的变化具有较为明显的影响作用。根据数值模拟结果,通过计算云图及指标对比得出了适用于本中间包尺寸及外形条件下的优选控流元件,并由现场实际温度的测量进行了验证。     

Optimization of flow control devices for a T-type five-strand billet caster tundish: water modeling and numerical simulation

The optimization of flow control devices(FCDs) for a T-type five-strand billet caster tundish was carried out by water modeling and numerical simulation. In water modeling experiments, flow characteristics of the bare tundish and tundish conf igurations with designed U-type baff les and a round turbulence inhibitor were analyzed using residence time distribution(RTD) curves. Mathematical models for liquid steel in the real plant tundish were established using the fluid dynamics software package Fluent. The flow field, the temperature field, and the RTD curves of liquid steel in the proposed tundish conf igurations were obtained. The results of numerical simulation and water modeling were validated with each other by the predicted and experimental RTD curves. The results of flow field and temperature field were used to ref lect the actual state of a real plant tundish and to choose the optimal FCD. Finaly, from the whole performance of the multi-strand tundish, the optimal scheme was determined by combining the results of water modeling and numerical simulation. With the optimal tundish equipped with U-type baffle with def lector holes and round turbulence inhibitor, not only was the flow characteristic of each strand improved, but also the difference of flow characteristics between multiple strands was smaller.     

连铸中间包带过滤体湍流抑制装置的水模研究

通过水模型实验初步研究了在湍流抑制器中加过滤体对中间包钢液流场和夹杂物去除率的影响。采用染色剂显示了中间包中的流动状态,用聚乙烯颗粒测定去除率。结果表明,由于过滤体的阻碍作用,延长了示踪剂到达挡墙导流孔的时间;加过滤体后不同粒径夹杂物的去除率都得到提高,将近5%。     

优化高拉速板坯连铸中间包控流装置的水模型和数值模拟

通过建立模拟高拉速板坯连铸中间包内钢液流动的水模型和数值模拟,研究了挡渣墙、坝和抑湍器等控流装置对中间包内流体流动特性的影响.结果表明,有无冲击板对中间包流动特性的影响不大,抑湍器与单墙双坝的合理搭配对中间包内夹杂物有效去除的流动特性十分重要,否则会起负面影响.提出了一个控流结构优化设计的方案.     

连铸中间包内夹杂物去除机理的水模型研究

通过选择乳状液滴模拟夹杂物和连铸中间包水模型实验,考察了控流装置、浇铸速度及夹杂物粒径对中间包内夹杂物去除行为的影响规律.结果表明:挡墙-挡坝组合控流去除夹杂物效果最佳,中间包内强湍流区夹杂物的碰撞、聚合以及向上和表面流速的增加是主因;中间包注流区加入冲击槽,虽然其流体流动特征发生改变,但对夹杂物去除率的影响并不显著;浇铸速度较高时,仅靠控流装置的优化已不能很好地改善夹杂物的去除效果.     

中间包吹气的水力学研究

以相似原理为基础,用水力学模型研究吹气对一流板坯中间包过程的影响.实验结果表明,吹气显著地改变了中间包内流体的流动特征;当不吹气时,流体在中间包内的平均停留时间较短,死区体积较大,不利于夹杂物的去除;吹气以后,气流上升形成气幕挡墙,增加了平均停留时间,缩小了中间包的死区体积,有利于夹杂物的去除.在3号位置使用A型透气砖,吹气量在150NL/h时,中间包内的流场最佳.     

连铸中间包内湍流控制器控流过程的数值模拟

采用ANSYS-CFX软件,针对宝钢4#连铸机中间包结构和操作工艺参数,进行了流动与传热耦合过程的三维数值模拟,并用水力学模拟进行验证。分析比较了无任何控流装置和有控流装置下的钢水流动以及RTD曲线,结果表明：设置湍流控制器可以使中间包内钢水流动死区减少,活塞区增大,更有利于夹杂物的去除。     

中间包流场数值模拟

针对邯钢三炼钢8机8流方坯连铸机中间包,通过建立数值模型,研究在设置挡渣墙和坝前后以及不同的挡渣墙情况下,中间包内钢水流场规律,并通过RTD曲线分析了连铸中间包内挡渣墙和坝对其钢液流场的影响,为优化方坯中间包钢水流场积累了很好的技术经验。     

六流T形连铸中间包内控流装置优化的水模试验研究

通过水模试验研究,对六流T形连铸中间包内的控流装置进行了优化。通过试验选择了控流较好的多孔挡墙形状,优化了多孔挡墙的开孔方向;研究了不同形状的湍流抑制器对中间包内钢液的控流效果。     

连铸中间包内钢液流动、传热及夹杂物行为的研究

建立基于黏性流体力学的流体流动、传热及夹杂物传输模型,以首钢第三炼钢厂2号连铸中间包为研究对象,采用数值分析的方法,进行了连铸中间包内钢液流体流动、停留时间分布及夹杂物传输行为分析.     

水平单带连铸弯月面区域的传输行为（英文）

利用改进的数学模型,通过数值模拟方法研究一种基于水平单带连铸的单冲击布流系统。采用中试铸机完成物理实验,从而对数值模拟结果进行验证。结果表明,弯月面处的湍流行为并非来自中间包,也不是来自熔体与冷却传送带的冲击。弯月面的高湍流能量来自传送带的移动,并且这个高湍流动能区可以搅动弯月面附近熔体。所研究的布流系统可与传送带共同构成一个缓冲区域,该区域的存在可避免工艺参数波动,尤其是中间包内熔池深度的变化。铸带底部的温度变化率比铸带表面的快大约4倍。     

A numerical analysis of fluid flow, heat transfer and solidification in the bending-type square billet continuous casting process

A numerical modeling system was developed which can simulate the transport phenomena of a bending type square billet continuous casting process. Fluid flow and heat transfer were analyzed with a 3-dimensional finite volume method (FVM) with the aid of an effective heat capacity algorithm for the solidification. For a complex geometry of the bending type billet caster, a body-fitted-coordinate (BFC) system was employed. The bent structure of the caster allows a recirculating flow to develop in the upper and outer-radius region and the main stream to shift toward inner radius. This causes the thinner solid shell in the inner radius region than in the outer one. Besides standard operation conditions, we have analyzed the results when casting speed, caster shape, and tundish superheat changes. Lower casting speed makes the solid shell thicker by reducing heat flux from the mold. In the vertical caster, solid shell thickness are more uniform than that in the bending-type in entire region. When superheat increases by 5°C, solid shell thickness at the mold exit becomes thinner by 1 mm.     

板坯连铸机全悬挂中间罐车设计与研究

全悬挂中间罐车通常用在方坯连铸机上,通过对中间罐车的结构及生产工艺分析后,在170 mm×880 mm板坯连铸机上首次采用了全悬挂中间罐车。本文对中间罐车结构进行了设计,对传动系统进行了计算。该设备在土尔其TOSYALI钢铁公司连铸机上使用,运行良好,解决了中间罐车下面设备维修困难问题、提高了生产率。     

控流装置对四流中间包钢水洁净度的影响

为了研究控流装置对中间包钢水洁净度的影响,采用数值模拟和工业试验验证结合的方法对钢厂方坯连铸中间包进行优化。通过在原型中间包基础上增加U型挡墙,使得响应时间增加5 s,峰值时间增加371 s,改善了钢液在中间包内的短路流现象;平均停留时间增加53 s,死区体积分数减小4.1%,活塞区体积分数增加17.3%,改善了夹杂物上浮的条件;各流一致性水平也得到了提高。工业试验结果表明,在受钢区与浇注区之间增加U型挡墙,使得中间包钢液中夹杂物去除率增加了29.05%,中间包各个区域夹杂物最大尺寸最大可减小26 μm,铸坯上夹杂物去除率增加38.42%,铸坯上夹杂物最大尺寸降至16 μm以下。在中间包中使用U型挡墙,提高了钢水的洁净度以及铸坯实物的质量。     

营钢8流小方坯连铸机工艺设计

介绍了五矿营钢8机8流方坯连铸机工艺设计特点、工艺流程、装备水平、工艺布置和主要物流路线，以及多流铸机情况下适应不同热送和下线比例的复杂出坯系统；详细分析了与同车间板坯连铸机交替使用同一给排水系统情况下的系统配置。     

不锈钢连铸中间包内夹杂物去除行为数值模拟

针对中间包连铸过程中夹杂物的存在易导致铸坯出现质量缺陷的问题,以不锈钢连铸中间包为研究对象,通过数值模拟方法研究了控流装置、夹杂物密度以及夹杂物尺寸等参数对中间包内夹杂物去除行为的影响规律。研究结果表明,在设置堰坝和湍流控制器中间包内,密度为2 700 kg/m3,粒径为5 μm的夹杂物去除率为63.32%,而150 μm的大尺寸夹杂物去除率可达到89.04%。当夹杂物粒径为10~50 μm,密度为2 700~4 500 kg/m3时,夹杂物密度对夹杂物去除率影响较小。无控流装置中间包时,夹杂物在顶渣层呈以中心纵截面对称的分布;设置堰坝中间包时,挡渣堰坝两侧出现了70 μm以上夹杂物密集区;设置堰坝组合湍流控制器中间包时,夹杂物主要被限制在中间包第一腔室自由液面,研究结果对于进一步发挥不锈钢连铸过程中的中间包冶金功能具有指导意义。     

连铸机中间包改造

中间包的寿命和优劣,直接影响着连铸机的产量和质量.同煤集团公司钢铁公司的连铸机经过改造,提高了中间包的寿命,降低了生产成本.同时,提高了产量,改善了铸坯的质量.     

通钢FTSC薄板坯连铸中间包控流装置的优化改进

借助水模试验,对通钢FTSC(Flexible Thin Slab Caster)薄板坯连铸中间包控流装置的形式、几何尺寸和位置进行优化改进。中间包的控流装置由原来的抑湍器、墙的单一组合优化为抑湍器、坝、墙的组合,生产实践中钢液流动特性有了明显改观,夹杂物总量减少50%以上,球状和大颗粒夹杂物等级明显降低,充分发挥了中间包冶金的作用。     

越南某钢厂小方坯连铸试生产失稳性诊断分析

越南某钢厂六流方坯连铸机在投产后的试生产过程中,生产很不稳定,事故停机频发,拉坯速度不超过2.5 m/min,试生产前期主要是漏钢停浇,后期主要是中间包快换水口盲板自动关闭停浇。通过对生产现场的工艺条件、操作流程、设备配置与工作状态等各方面的观察和排查,结合连铸漏钢机制、自动停浇诱因对事故进行了分析,提出从浇注操作的规范与熟练、结晶器振动的可靠性、水口质量、结晶器卷渣、切后铸坯拥堵的人工干预等方面进行改进的措施。逐步落实各项改进措施后,目前该厂生产平稳,拉速达到了3.25 m/min,漏钢及水口盲板自动关闭停浇等生产事故得到了显著改善。