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%.     

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.     

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.采用小高度湍流控制器加上下挡墙的控流方式时,由于钢水流经路径增长和全混流体积分率增加,响应时间增长,死区体积分率显著减小至15%以下,有利于夹杂物上浮去除.同时,将小高度湍流控制器和门式开孔导流坝相结合,残钢量显著减小,有利于提高金属收得率.     

中间包控流装置对温度场影响的数值模拟研究

通过对六流连铸机不同控流装置中间包内钢液温度场的数值模拟,提出了采用导流隔墙的改进方案.这种导流隔墙的应用,有利于均匀钢液温度,促使夹杂物上浮.     

五流大方坯连铸中间包流场与温度场数理模拟的研究

基于数理模拟,对五流大方坯连铸中间包内钢水流动特性及温度场进行了研究.物理模拟结果表明:采用湍流控制器可明显延长钢水的响应时间和停留时间,采用梯形围墙有利于钢水在各流间合理分配,在2#、4#流水口下游设置挡坝,能够进一步改善中间包内钢水的流动特性.当采用稳流器+梯形围墙+挡坝的控流方式时,各流的流动特征参数一致,死区体积在25.0%以下,平均停留时间达15 min以上;数值模拟结果表明,采用本研究开发的控流方式,中间包内钢水温度分布合理,包内钢水最大温差在10℃以内,各流间出口钢水温差为2～3℃,有利于发挥中间包的冶金效果,保证连铸生产顺行和铸坯质量.     

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。     

镁质中间包绝热板的研制

介绍一种新型隔热耐火材料，该板用ＭｇＯ〉９５％的烧结镁砂和Ａｌ２Ｏ３〉３８％的漂珠的主要原料，以及适量的纤维，结合剂，添加剂研制出体积密度１．４６ｇ／ｃｍ＾３，导热系数０．４６Ｗ／ｍ．Ｋ，抗折强度６ＭＰａ的镁质绝热板。     

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.     

板坯连铸中间包钢液流场的数学模拟

利用计算机数学模拟的方法,对中间包内钢液流场进行研究,以济钢一炼钢厂4#板坯连铸中间包为模型,以挡墙分别距入口处、挡坝间的距离,挡墙和挡坝高度为影响参数,对板坯连铸中间包流场进行优化设计.得出有利于生产的设计数据.     

Validation of the numerical simulation of fluid flow in the continuous casting tundish

The 3-dimensional fluid flow in a water model of the continuous casting tundish is simulated with the k-ε two-equation turbulence model. The methods to decide the size of wall-adjacent grids and the effects of residuals and mesh size on the simulation accuracy are discussed. The current investigation concludes that the following condition should be satisfied to get accurate enough simulation results: (1) If the dimension of the domain is in the order of cubic meters, the average size of cells in the mesh system should be at least smaller than 30 mm; (2) The normalized non-scaled residual should be reached at least smaller than 10^-4.     

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...     

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％.     

注入钢液温度降低时中间包非稳态过程数值模拟

利用所建立的中间包非稳态传输过程数学模型对包浇注一个包次周期中中间包工作过程进行了数值模拟.在中间包非稳态过程模拟中首先采用稳态速度场和温度场作为计算的起始速度场和湿度场,以此为基础,完成一个包次浇注过程的计算后,用其所得物理场作为初始速度场和湿度场,进行中间包注入钢液温度降低所产生的非稳态过程模拟计算.模拟结果表明,这样处理更加逼近中间包的真实状态.通过对数值模拟结果的分析,发现在钢包一个包次浇注过程中,中间包中出现两次"流动逆转"和"温度逆转",且第一次逆转有利于中间包冶金功能的发挥,第二次逆转的作用相反,应设法避免和推迟中间包内第二次逆转现象的出现.     

Orthogonal analysis of water model study on the optimization of flow control devices in a six-strand tundish

Improper flow control devices in a multi-strand tundish can cause some problems, for example, liquid steel cannot reach every nozzle at the same time and the liquid steel in nozzles far away from the entry zone has a lower temperature. The water model experiment of a six-strand tundish of Tianjin Iron ＆ Steel Co. Ltd. was performed, a new ＂U＂ type baffle was obtained, and its parameters were defined by perpendicular analysis. The ＂U＂ baffle can not only improve those imperfections, but also prolong the residence time of nonmetallic inclusions, which is good for their flotation and separation.     

Fluid flow in large-capacity horizontal continuous casting tundishes

The configuration of the tundish for a two-strand horizontal continuous caster was designed and optimized through water modeling. Three designs of the tundish were studied: the original tundish without any flow control devices, the tundish with a turbulence inhibitor at the bottom, and the tundish with an inlet launder and an inclined dam. The residence time, the location and size of the dead zone, and the fluid field pattern were investigated. At the same time, the asymmetry flow field and wavy inlet jet in the horizontal tundish were observed and the reasons for them were discussed. The results indicate that the tundish with an inlet launder and an inclined dam is the best of the three designs.     

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。