中间包隧道式过滤器的物理模拟

在1∶2的中间包水模型上,采用物理模拟的方法对中间包安装隧道式过滤器前后的流场进行研究,分析过滤器出口角度、挡坝高度等因素对流场的影响。结果表明:中间包隧道式过滤器不仅能过滤钢液,还能与其他控流装置组合使用,优化中间包流场,为进一步降低钢中夹杂物提供了一种选择;方案为过滤器出口角度20°,挡坝高度350 mm,能够很好地优化中间包流场,有效降低死区体积分率,增加活塞区体积分率,延长钢液的平均停留时间,使夹杂物上浮去除条件得到进一步改善。     

中间包流场数值模拟

利用大型流体计算软件Fluent,对马钢连铸中间包的流场进行数值模拟.将模拟计算结果与现有中间包存在的实际现象对比表明,中间包在现有结构条件下分流和控流装置获得的流场分布不利于中间包钢水中夹杂物的控制和去除.通过改变原有中间包挡墙结构,从而改变中间包内流场分布,彻底改变了中间包中的流型结构,延长了流体质点的运动轨迹,增加了钢液的平均停留时间,为微型夹杂物的去除提供了有利条件.     

六机六流中间包流场优化水模研究

根据相似原理,利用水模拟钢液流动,研究中间包内流场的流动情况。在不同方案的内腔设计下,分别进行水模型试验,通过计算机采集相关数据,对比由计算机采集数据绘制成的RTD曲线及用墨汁作为示踪剂的流场照片,寻求出最优化方案。经过改进的中间包各流平均停留时间较长,不同流量的平均停留时间分别为459,380,374s;死区体积最小,死区平均体积分数为15．1％,中间包内流场得到了优化。     

中间包控流装置的物理模拟研究

根据相似原理,建立1∶3的物理模拟模型,通过正交试验考察了挡渣堰、导流坝组合控流装置对中间包流场的影响。研究结果表明,堰坝间距是影响流场的主要因素,优化控流组合方案为：挡渣堰距注入流中心线距离1 200 mm,挡渣堰下沿距包底距离500 mm,导流坝高度360 mm,堰坝间距300 mm.优化后中间包流场趋于合理,钢液在中间包内的停留时间延长,活塞流体积增大,死区体积减小.     

二流连铸中间包内型优化水模试验

以相似原理为基础,用水模拟钢液研究中间包内的钢水流动特征,通过测定模型中间包内停留时间分布曲线(RTD),计算其平均停留时间及死区、活塞区和混合区的体积。试验表明,经过改进的中间包,其最短停留时间由20s增加到54s,平均停留时间由249s增加到305s,死区体积则由30．34％降低到14．74％,优化了中间包内的流场。     

七流连铸中间包流场的数值模拟

采用FLUENT软件对中天钢铁集团公司七流连铸中间包内型流场进行数值模拟,研究速度矢量、湍动能和流体迹线分布规律,分析中间包内有无C型挡墙加入的流场特征.模拟结果表明,加入C型挡墙使中间包的湍动能主要集中在入口区域,利于延长包内各流的平均停留时间,减小死区体积分数,包内各流流动更加均匀,有利于钢液温度和成份的均匀.     

首钢中间包优化设计(Ⅰ)

应用湍流流动数学模型研究了首钢中间包内钢液的流动与混合 ,该模型包括求解三维湍流的N -S方程和k -ε双方程模型 对首钢第二炼钢厂现有中间包的流场和钢液的停留时间做了模拟与分析 ,并预报了在不同位置加设不同高度的坝后 ,中间包内钢液的流动状态及停留时间 结果表明 ,如果坝的设置不当 ,中间包内钢液的流动状态则会更差     

板坯中间包控流装置结构优化的水模研究

根据相似原理,按照1：2比例对中间包建立水力学模型。考虑坝高、堰离底部高度、坝堰间距、堰与长水口注入点间距等参数对中间包内流场的影响,依据工厂实际工艺参数设计实验方案。对实验结果进行分析,结果表明：对原中间包结构进行优化,减小堰离底部距离及堰与注入点间的距离,钢液在中间包内响应时间由69.0 s延迟至75.0 s,平均停留时间由418.0 s增长至555.4 s,死区体积比例则由28.4%降至18.3%。     

五流大方坯中间包流场优化

针对某钢厂五流大方坯中间包3流铸坯探伤不合格率较高的问题,采用数值模拟方法,研究不同结构中间包钢液的流场。结果表明,该钢厂现使用的中间包结构不合理,近流有短路流出现,且各流差异较大,不利于去除钢液中的夹杂物和提高各流间钢液的均匀性;采用大冲击区,挡墙中墙不开孔、侧墙开4个孔,设置2个坝的中间包结构最佳;中间包结构优化后,消除了近流的短路流,中间包钢液平均停留时间达652.9 s,各流示踪剂浓度的标准差仅为0.011 9,死区体积分数也仅为21.96%,既有利于夹杂物上浮去除,也保证了各流间钢液的均匀性。     

70t连铸中间包内钢液流动的物理模拟

以某钢厂70 t两流中间包为原型,用物理模拟的方法对两流中间包流场特性进行研究。在中间包内腔设置不同的挡堰深度、挡坝高度与坝堰间距等控流参数,分析其对中间包内流场的影响,通过比较不同控流参数下中间包内流体停留时间分布(RTD)曲线,最终确定中间包控流工艺的优化方案。结果表明:中间包工作液面高度为440 mm时,最佳的中间包控流工艺参数为挡堰深度80 mm,挡坝高度100 mm、坝堰间距120 mm。     

Fluid Flow in Tundish Due to Different Type Arrangement of Weir and Dam

Tundish is an important metallurgical reactor in the continuous casting process,In order to control the fluid flow in tundish and thus take full advantage of the residence time available for the removal of inclusions from molten steel,the effect of weir and dam on the fluid flow has been studied in a water model based on the characteristic number Froude and Reynold number similarity criteria.The residence time distribution curves of the flow were measured by SG800,The optimum arrangement of dam and weir and the nonstationary flow in tundish were discussed.The results show that the comnbination of weir and dam is benefit for the flow pattern in tundish,weir can prevent the upper recirculating flow.dam can cut off the bottom flow and turn to upwards,it is advantageous to separate the nometallic inclusions.Furthermore,it is importnat to exceed the critical depth of bath during exchange ladles,not only for the inclusion floatation but also for avoiding tundish slag drainage earlier.     

Improvement of tundish shape and optimization of flow control devices for sequence casting heavy steel ingots

The metallurgical effect of a round tundish used to cast heavy steel ingots in machine works at present was evaluated through water modeling experiments.The flow control devices of the improved oval tundish,which was used instead of the round tundish,had been optimized.The results show that the residence time of the round tundish is short,its inclusion removal efficiency is too low,and it has more dead zones and an unreasonable flow field.Compared with the round tundish,the improved oval tundish with the optimized weir and dam has a better effect:its minimum residence time is prolonged by 38.1 s,the average residence time is prolonged by 233.4 s,its dead volume fraction decreases from 26％ to 15％,and the ratio of plug volume fraction to dead volume fraction increases from 0.54 to 1.27.The inclusion removal efficiency also increases by 17.5％.     

Application of Computational Fluid Dynamics to analysis of metallurgical process for continuous casting tundishes

A series of simulations by mathematical and physical modeling on fluid flow, mass and heat transfer in continuous casting tundishes have been carried out. It was found by computational fluid dynamics (CFD) simulation that in most cases tundish flow must be treated as a non-isothermal reactor due to the existence of temperature difference between the transport ladle and the tundish. The critical conditions when the non-isothermal flow in the tundish can not be neglected have been found by CFD simulation and water modeling. A direct measurement in a 40 t tundish has confirmed the simulation results.     

Dissymmetric flow phenomenon in a multistrand tundish

The dissymmetric flow phenomenon exists in a symmetric multistrand tundish. It was studied by the physical simulation experiment. The fundamental flow characteristic of dissymmetry was analyzed. The asymmetry of the flow field, the temperature field, and the inclusions distribution without flow-control devices (FCDs) were compared with those with FCDs. It is proved that the asymmetry of the flow and temperature field along the outlets at the long range is more obvious. The symmetric FCDs installation has a slight effect on the dissymmetric temperature field, simultaneously, the symmetry of the average residence time and the fluid flow pattern has improved, and the fluid flow in the tundish has been more reasonable. In case of a symmetric multistrand tundish having a large volume, the influence of the dissymmetric phenomenon should be considered and the flow behaviors in the whole tun- dish should be studied completely.     

Optimization of flow control devices in a single-strand slab continuous casting tundish

The optimization of flow control devices in a single-slab continuous casting tundish was carried out by physical modeling, and the optimized scheme was presented. With the optimal tundish configuration, the minimum residence time of liquid steel was increased by 1.4 times, the peak concentration time was increased by 97%, and the dead volume fraction was decreased by 72%. A mathematical model for molten steel in the tundish was established by using the fluid dynamics package Fluent. The velocity field, conc...     

Design optimization of flow control device for multi-strand tundish

The fluid flow phenomena in tundish have a strong influence not only on the uniform of composition and temperature of bath, but also on the separation of non-metallic inclusions, especially for the multi-strand tundish. A water model of a multi-strand tundish has been set up based on the Froude number and Reynold number similarity criteria. The effect of dam+weir and baffle on the uniform of composition and temperature of bath for different nozzles has been studied. The residence time distribution curves of the fluid flow were measured by SG800. Comparing the photos of the flow pattern in tundish, the optimum arrangement of baf-fle+dam was obtained. This new structure is benefit not only to uniform the temperature among different SENs (submerge entry nozzles) but also to separate the non-inclusions from the liquid steel, it can be widely used in multi-strand tundish.     

两流板坯连铸中间包结构优化水模实验研究

通过两流板坯中间包水模实验,研究了抑湍器以及不同控流装置的组合对中间包流动特性的影响.结果表明,合理使用抑湍器能延长开始响应时间,提高平均停留时间和活塞流体积.抑湍器和垱坝组合控流效果良好,且结构简单.由抑湍器、垱坝和挡渣堰组成的控流装置使中间包流场更加合理,优化后的中间包平均停留时间由原先的188 s提高到218 s,活塞流体积分数由3.50%提高到15.41%,死区体积分数由41.57%降低到32.15%.     

五流连铸机中间包结构研究

应用湍流流动的数学模型研究五流连铸机中间包内钢液的运动,对某厂五连铸机中间包的流场作了模拟和分析,结果表明,该中间包存在一些问题,指出了改进的方向。     

基于RTD曲线连铸中间包优化设计数值模拟

为了优化连铸中间包内型,采用数值模拟方法计算钢液在连铸中间包内的停留时间分布（RTD）,并通过RTD曲线分析了连铸中间包内挡坝高度和位置对其钢液流场的影响。结果表明,结构优化后的连铸中间包钢液流场趋于合理,死区体积分数由原始方案的17.62%降至13.29%,且钢液在连铸中间包内的停留时间变化不大。     

八流中间包内型优化水模实验

根据相似原理,利用水模拟钢液流动来研究中间包内流场的流动状况,通过调节中间包内挡墙位置及其开孔大小来改善和优化中间包内的流场。对比计算机采集的RTD数据及用墨汁作为示踪剂的照片寻求出最优化方案。得出经过改进的中间包各流平均停留时间增加50-90s,死区体积由25％～30％降低到14％～19％,活塞流的体积比从8％～13％增加到26％-27％,优化了中间包内的流场。