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。     

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。     

板坯连铸中间包内钢液流场和浓度场的数值模拟

采用FLUENT软件对板坯连铸中间包内的流场和浓度场进行数值模拟,分析中间包内有无挡墙以及挡墙参数变化引起中间包内流场、浓度场的变化情况。模拟结果表明,湍流控制器与挡墙的优化配合使中间包内钢液的平均停留时间由502 s延长至573 s,死区体积分数由29.7%降为14.4%,优化挡墙与挡坝参数有利于钢液温度和成份的均匀,及夹杂物的上浮去除。     

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%。     

钢水密度对中间包流场影响的数模研究

利用数模研究了钢水在常密度和密度变化两种条件时，中间包内的流场、温度场和钢水平均停留时间．计算结果说明高温钢水在中间包内流动时，不能忽略自然对流流动，密度随温度变化时，钢水沿着液面流到水口区，没有短路流现象，最短滞流时间150s，进出口温差46℃，其流场和温度场与常密度条件下的正好相反．     

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。     

二流中间包内型优化的水模实验研究

通过水力学模拟和正交实验方法,采用挡墙和挡坝的控流装置,优化二流中间包的流场.采用正交分析方法优化出最佳方案,得出优化后的中间包示踪剂响应时间从17s提高到48 s,平均停留时间从240 s增加到427 s,中间包死区体积比也从48.0%减少到7.5%.     

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%.     

板坯连铸中间包底吹气数值模拟研究

根据宝#连铸机中间包的实际操作工艺参数,在中间包结构内部加装吹气装置,进行了气-液两相的流动和传热耦合的数值模拟.模拟研究结果表明,底吹气可以显著改善中间包内钢水的流动特征,增加钢水流动的轨迹,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;在坝堰中间加装吹气装置有助于均匀整个中间包内钢水的速度,减少中间包的死区体积分率,得到更好的冶金效果.     

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.     

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％.     

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...     

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.     

Numerical investigation of the effect of transitory strand opening on mixing in a multistrand tundish

In a multistrand,the outlet near the inlet produces short circuiting flow.This leads to the formation of dead zones inside the tundish,and consequently,the mean residence time decreases.In the present study,numerical investigation of mixing inside a delta shaped tundish with sloping boundaries was carried out by solving the Navier-Stokes equation and employing the standard turbulence model.To decrease the dead zone volume inside the tundish,the effect of closing the outlet near the inlet for a small amount of time and further opening it on the mixing behavior of the tundish was studied.The outlets near the inlet were closed for varying amount of time,and the transient analysis of fluid flow and the tracer dispersion study were carried out to find the mixing parameters of the tundish,namely,mean residence time and the ratio of mixed to dead volume of the tundish.An optimum closure time of the near outlet has been found,which yields best mixing inside the tundish.The numerical code was validated against the experimental observation by performing the tracer dispersion study inside a multistrand tundish and the reasonably good match between the experimental and numerical results in terms of residence time distribution (RTD)curves.The results obtained from the present study confirm the strong role of choosing the right time for opening and closing the outlets to get improved characteristics for the fluid flow and mixing behavior of the tundish.The educational version of computational fluid dynamics(CFD)soft ware PHOENICS was used to solve the governing equations and interpret the results in different forms.