气体流量及水口底部形状对板坯结晶器内流场影响的水模型试验

采用1:1水模型研究了气体流量（010 L/min）和水口底部形状（凹底和尖底）对结晶器内流场的影响。在结晶器断面为230mm×1 200 mm,浇铸速度为1.6 m/min的模拟工况条件下,凹底水口其流体形态优于尖底水口;在结晶器液面波动稳定性方面凹底水口亦优于尖底水口;气体流量在08 L/min,使用尖底水口的流体其表面流速明显高于使用凹底水口的流体;对凹底水口而言,气体流量超过8 L/min,其流体表面流速低于0.2 m/s;120炉IF钢生产结果表明,使用优化的凹底水口和吹氩流量7 L/min,浇铸过程结晶器液面波动在±3 mm以内,铸坯夹杂物比优化前降低24%。     

Effects of Nozzle Radial Position,Separation Angle,and Gas Flow Partitioning on the Mixing,Eye Area,and Wall Shear Stress in Ladles Fitted with Dual Plugs

Metallurgical and Materials Transactions B - Mixing time, slag eye area, and wall shear stress in a ladle fitted with dual plugs have been studied as a function of operating variables,...     

Fluid Flow,Dissolution, and Mixing Phenomena in Argon-Stirred Steel Ladles

Metallurgical and Materials Transactions B - In the current study, the multiphase fluid flow in argon-stirred steel ladles is simulated using an Eulerian–Lagrangian two-phase approach. The...     

顶底复吹转炉底吹流量优化控制技术

通过理论与实践相结合,开发出一种性能优良的流量调节算法-专家变参数PID调节算法,实现顶底复吹转炉底吹流量优化控制。在30～120 t顶底复吹转炉的实际应用表明,专家变参数PID控制技术具有优良调节性能,实际底吹流量曲线控制平稳、迅速,流量控制精确,有效防止底枪堵塞,明显提高了经济效益。     

Effect of Bath Depth and Nozzle Geometry on Spout Height in Submerged Gas Injection at Bottom

Metallurgical and Materials Transactions B - Spout height is a widely used parameter to quantitatively analyze the performance of the submerged gas injection in industrial applications. However,...     

精炼钢包底喷粉透气砖的研制与实验研究

针对传统钢包喷粉工艺的不足，开发了从钢包底部喷吹的喷粉型狭缝式透气砖。这种带锥形流化室的透气砖，既可用于钢包底吹气又可用于钢包底喷粉，在冷热态条件下进行了实验并获得成功。     

底吹熔池流体流动的数学物理模型

本文推导了底吹熔池流场中两相区的含气率公式和密度公式,修正了涡量传输方程中的源项,改进了前人关于底吹熔池流体流动的数模。本数学模型预报的结果与水模型中实验测量结果相符。     

底吹炉氧枪喷口形式对气泡形态及混合状况的影响

针对4种不同的氧枪喷口结构进行了冷态试验研究,采用高速相机获得了不同喷口下的炉内气泡形态,采用电导率法测试了不同喷口下炉内流体的混合状况。试验结果表明,在相同的气体流量下,不同的气体喷口时炉内气泡的形态十分相似,当采用结构最复杂的喷口时,炉内的混合状态是最好的,结构最简单的喷口混合效果最差,其最小响应时间较最复杂喷口增加约11%,均混时间增加约4.7%。     

底吹钢包内流动及混合的两相流数值模拟

应用欧拉-欧拉模型建立了钢包内钢液流动及混合过程的数学模型,考察了吹气量对中心底吹及偏心底吹钢包内流场及均混时间的影响。计算结果表明,钢包底部四周为流动缓慢区域;吹气量越大,一方面可以降低均混时间,另一方面会导致钢包自由液面的钢液流速增大,从而容易造成卷渣;从缩短混合时间,提高生产效率考虑,偏心底吹更为有利。     

Simulation of Gas Flow Field in Laval Nozzle and Straight Nozzle for Powder Metallurgy and Spray Forming

Gas flow field in nozzles and out of nozzles was calculated for Laval orifice and straight orifice nozzles. The results showed that the flow generated by the Laval nozzle had a higher exit velocity in the vicinity of the nozzle, in comparison with that of the straight nozzle, that is to say, a Laval nozzle was more efficient than a straight one in disintegrating the melt stream and was apt to produce finer powders. The flow generated by the Laval nozzle was less convergent and the velocity gradient along the radial direction was more moderate than that of a straight nozzle, which could contribute to a broad distribution of melt particles. According to their flow characteristics, the Laval nozzle was reckoned as a better choice of producing larger spray-formed billets.     

钢包底吹对钢液混匀时间和排渣面积的影响

通过实验室水力模型实验,研究了钢包底吹方式、气体流量对钢液混匀时间、液面排渣面积的影响。实验结果表明,采用双孔底吹方式可使钢液混匀时间缩短,液面排渣面积减少,为在生产中使用合理的钢包底吹方式以及控制气体流量,有效促进夹杂物去除及减少卷渣提供依据。     

全氢罩式退火炉循环风量对退火时间影响分析

循环风量是全氢罩式退火炉的关键设计参数之一。通过建立全氢罩式退火炉炉内传热过程的数学模型 ,并经过实测验证后 ,分析了循环风量与退火时间的关系。结果表明 ,循环风量的增加与退火时间的缩短之间不存在简单的比例关系 ,设计中应该采用适当的循环风量     

顶燃蓄热式热风炉底部空间空气流动特性模拟研究

顶燃蓄热式热风炉具有蓄热面积大、结构对称强度高、热效率高、送风温度高、生产维护费用低和使用寿命长等优点,具有广阔的发展前景。优化热风炉结构、改善流动状况、提高热风炉风温是目前热风炉研究的重点方向。本文通过建立顶燃蓄热式热风炉底部空间内气体流动的三维数学模型,模拟底部空间内空气的流动过程,分析空气流经支撑柱绕流时的流动规律,对比研究不同挡板结构对底部空间内流场及进入蓄热体气体流动均匀性的影响,从而获得最优化的挡板结构。研究结果对热风炉结构优化、进一步提高热风炉风温、节约能源和保护环境有指导意义。     

吹气管内径对RH精炼过程钢液流动和混合特性的影响

水力学模型和90t RH精炼装置原型的线性比例为1：5。模型吹气孔直径分别为0．8mm和1．2mm。试验结果表明，在给定的吹气量Qg、上升和下降插入管直径Da和Dd下，吹气孔直径din的增大并不显著改变RH精炼过程中钢液流动特征，但是环流量Ql随吹气孔直径din的增大而增大，其关系式为：Q1=2．40Qg^0.23Du^0.72Dd^0.88din^0.13；0．8mm和1．2mm孔径下的混合时间τm与搅拌能密度ε的关系分别为τin∝ε^0.5和τm∝ε^0.49     

SEN底部形状对结晶器内钢液流场和温度场的影响

针对某钢厂板坯连铸结晶器及浸入式水口(SEN)的结构参数,建立了描述结晶器内钢液流动的三维数学模型,应用FLUENT软件对结晶器内钢液的流场和温度场进行耦合计算,分析SEN底部形状对结晶器内流场和温度场的影响,并利用水模试验对钢液的流动行为进行了验证。结果表明:凸底水口出口附近钢液的速度较大,流股的冲击深度较大,使结晶器内高温区下移,不利于凝固坯壳的生长;平底水口自由面速度较大、温度较高,有利于保护渣的熔化,但易产生液面裸露现象;凹底自由面速度较小、温度较低,有利于液面稳定。     

透气砖布置和吹氩流量对钢包内钢液流动行为的影响

针对攀钢200t钢包,采用物理模拟与数值模拟相结合的方式,研究了透气砖布置方式和吹氩流量对钢液流动行为的影响规律。结果表明,当两透气砖呈120°布置在距包底中心0.62R(R为包底半径)处时,钢液的平均流速和平均湍动能大,"死区"范围小,混匀时间短,是合理的透气砖布置方式,其临界吹氩流量为27m3/h;与单透气砖相比,双透气砖喷吹的能量利用率高,"死区"范围小,单透气砖的吹氩流量需控制到45m3/h才能达到与双透气砖吹氩流量为27m3/h时相同的搅拌效果。实践证明,研究得到的透气砖布置方式和吹氩流量能保证熔池的搅拌效果,使转炉钢水经吹氩处理后,钢包不同位置温差小于10℃,Δw[C],Δw[Si],Δw[Mn]小于0.03%;在一定的软吹氩流量条件下,吹氩时间大于等于8min,可以使钢中wT[O]小于25×10-6。研究表明,用离散相模型对钢包底吹氩过程进行数值模拟,可以得到与物理模拟试验和生产实践较为吻合的结果。     

Physical Modeling of Fluid Flow in Ladles of Aluminum Equipped with Impeller and Gas Purging For Degassing

In the current study a transparent water physical model was developed to study fluid flow and turbulent structure of aluminum ladles for degassing treatment with a rotating impeller and gas injection. Flow patterns and turbulent structure in the ladle were measured with the particle image velocimetry technique. The effects of process parameters such as rotor speed, gas flow rate, and type of rotor on the flow patterns and on the vortex formation were analyzed using this model, which control degassing kinetics. In addition, a comparison between two points of gas injection was performed: (a) conventional gas injection through the shaft and (b) a “novel” gas injection technique through the bottom of the ladle. Results show that the most significant process variable on the stirring degree of the bath was the angular speed of the impeller, which promotes better stirred baths with smaller and better distributed bubbles. A gas flow rate increment is detrimental to stirring. Finally, although the injection point was the less-significant variable, it was found that the “novel” injection from the bottom of the ladle improves the stirring in the ladle, promotes a better distribution of bubbles, and shows to be a promising alternative for gas injection.     

搅拌部位及强度对底吹电弧炉熔池混合特性的影响

在３０Ｔ底吹电弧炉１：７水模型的基础上，研究了搅拌部分对ＫＣｌ溶液电导率值变化的影响及熔匀时间与搅拌功率密度的关系，作出了溶液等混匀时间曲线。结果表明，底部吹气搅拌可强化电弧炉熔池的均匀混合，其混合速度底部快于表面，中心快于边缘