65t钢包底吹氩过程混匀时间模拟研究

根据唐钢实际生产工艺要求,以LF精炼过程65 t钢包为研究对象,采用fluent数值模拟及物理模拟相结合的方法研究了65 t钢包底吹喷孔中心间距、底吹喷孔夹角、底吹流量对钢液混匀时间的影响规律。结果表明,当65 t钢包底吹孔中心间距为0.6R、喷孔夹角为180°、底吹流量为250 NL/min时,钢液的混匀时间最短。当吹氩量为100 NL/min时,钢液的搅拌能力较强,可以避免卷渣的发生,混匀时间为307 s。同时,数值模拟与物理模拟的混匀时间误差在5%以内,进一步验证了数值模拟结果的准确性。     

插入浸渍圆筒钢包底吹气体优化研究

以150 t钢包为原型,采用水模型实验的方法研究插入浸渍圆筒底吹钢包内钢液的卷渣现象,研究了底吹气量、浸渍圆筒直径及插入深度对钢液卷渣及均混时间的影响。同时建立钢包底吹气体钢液流场数学模型,利用Mixture多相流模型对钢包吹氩过程进行数值模拟计算,分析不同底吹气量下插入浸渍圆筒钢液的流动状态和钢液表面的卷渣。通过水模拟和数值模拟比较,结果表明:插入浸渍圆筒后,增大了临界卷渣吹气量,加强了熔池搅拌,更有效地缩短了混匀时间。     

LF顶吹喷枪的数值模拟及工艺优化

以某厂180 t精炼钢包及顶吹喷枪设备为研究对象,数值模拟建立物理模拟。目的是优化工艺和改善动力学条件。应用N-S方程和[k-ε]双方程模型对LF炉外精炼顶吹喷枪和钢包内钢液流动行为数值模拟。研究结果表明：采用水平侧吹喷孔替换倾斜侧吹喷孔的设计方案,已达到减小钢液喷溅。模拟分析得出顶吹喷枪低枪位比较高枪位搅拌动能较大。     

吹氩精炼饮包内三维流动和混合现象的研究

利用开发的三维适体数值计算软件对吹气精炼钢包内的流动和混合过程进行了数学模拟，考察了操作参数对钢包内流动方式和混合的影响。提出了描述钢包内混合时间的代数表达式和合理的喷吹位置。数值模拟结果与实测值在定量上吻合较好。     

吹氩精炼钢包内三维流动和混合现象的研究

利用开发的三维适体数值计算软件对吹气精炼钢包内的流动和混合过程进行了数学模拟，考察了操作参数对钢包内流动方式和混合的影响，提出了描述钢包内混合时间的代数表达式和合理的喷吹位置．数值模拟结果与实测值在定量上吻合较好．     

钢包吊摆-液晃耦合建模与动态特性研究

为研究钢包吊运过程中钢液晃动与吊摆的耦合情况及影响因素,根据等效动力学原理建立了钢包吊运系统的质量-弹簧-阻尼模型,推导出了其运动方程,建立了钢包吊运系统的多体动力学-两相流有限元耦合模型进行有限元数值模拟,验证了三阶模态等效模型的有效性。然后基于等效模型分析不同参数对钢包吊运系统的影响。结果表明：钢丝绳摆动幅值随着绳长的增加先增加后减小,在钢丝绳长8 m附近时达到最大值,且摆动幅值随着小车加速度的增加而增加。钢液晃动的剧烈程度随着钢包载液率的增加而减小。钢液晃动会随着钢丝绳长的增加而减小,但是随着钢包载液率的增加,这种影响越来越小。该等效模型可为钢包吊运系统的精准定位控制方案提供理论基础。     

燃气射流式钢包烘烤器的设计及应用

介绍了钢包烘烤器的发展现状,分析了燃气射流式钢包烘烤器在燃烧状况中的优势,并对其燃烧过程进行了模拟分析及空燃比的研究。结合天津某公司120 t钢包烘烤器的改造实例,设计了新型燃气射流式钢包烘烤器。实践表明:改造后,钢包的最高温度由1 000℃提高到1 200℃,在线烘烤时间由7 h缩短到4 h,煤气消耗量由1 320 m3/h减少到716.6 m3/h,达到了节能减排的要求;燃烧管采用310S不锈钢,延长了钢包烘烤器的使用寿命。     

120t钢包底吹氩混匀过程的数值模拟研究

以某钢厂120 t单孔底吹氩钢包为研究对象,利用ANSYS-FLUENT软件对不同吹氩条件下钢包内钢液的流场进行数值模拟,并预测混匀时间。结果表明,吹孔位置位于1/2R处,氩气流量为100 L/min时,钢液的混匀时间最短,钢包内钢液的搅拌效果最好。     

超声波钢包精炼数值模拟

以150t钢包为原型,采用FLUENT数值模拟软件研究超声波对改善钢液搅拌效果、优化超声波工作杆和频率的作用。模拟结果表明:超声波能够改变钢包内部的压力分布,有利于去除夹杂物和气体;超声波工作杆位置为0.52 H时产生负压的位置较佳,有利于减少超声波能量的损失,充分发挥超声波净化作用;频率范围在20~40 k Hz时,频率越大,空化作用越大。     

底吹钢包内流动与混合的数值模拟

利用数值模拟的方法对几种典型喷吹方式的底吹钢包内的流动与混合过程进行了理论分析结果表明,变化喷吹方式,即从中心喷吹到偏心喷吹、从单喷嘴喷吹到双喷嘴喷吹,钢包内的流动混合状态得到改善,因而有助于缩短钢包内的均匀混合时间     

基于数值模拟技术的钢水温降速率预测

通过建立钢包传热数学模型和有限元模拟计算,分别采用代表值法和能量守恒法分析重钢炼钢厂210t钢包不同烘烤温度、不同绝热层材质对钢水温降速率的影响,并对不同工况的钢水温降速率作了预测。结果表明:代表值法和能量守恒法计算的钢水温降速率有较大差异;钢包烘烤温度对钢水温降速率影响很大;钢水浇注过程中温降速率比静置的要大。     

锥桶形浇包余液体心矩有限元模型探索与算例

铁液包倾转力矩是铁液包结构设计中一个重要问题。本文采用有限元法建立了铁液包倾转力矩数学模型。将铁液包余液的体积分成斜锥台和正锥台两部分,然后求解。其关键点是采用有限元法把斜锥台分割成n个弓形片状有限元体,从而推导出斜锥台部分的体心矩数学模型,采用数值迭代法求解。这种方法能够简单有效地解决铁液包倾转力矩求解问题,对铁液包结构设计具有积极意义。最后用实例来说明算法的有效性。     

感应加热钢包炉的电磁与结构分析

通过电磁场数值计算，对国外感应加热钢包炉的电磁设计及包壳结构进行分析，为国内开发、应用和优化感应加热钢包炉提供基础。     

Research Progress of Numerical Simulation in Steelmaking and Continuous Casting ProcessesEI北大核心CSCD

Because of the complexity of steelmaking and continuous casting processes and their limitation condition for direct measuring and testing, numerical simulation has become an indispensable means to analyze the phenomena and mechanisms occurring in the processes, and since the 1980s, it has made a rapid development. For the converter smelting, some new oxygen lances were designed by using the simulation study of the characteristics of the oxygen lance supersonic jet. Some mathematical models have been established to describe the slag-metal-gas multiphase flow behavior in steelmaking converter, and the flow field, mixing efficiency, metal droplet splashing, lining scouring and other physical phenomena. For the ladle refining, the Euler-Euler model gradually replaces the quasi-unidirectional and Euler-Lagrangian models, and successfully describes the phenomena of bubble turbulent dispersion caused by liquid turbulent fluctuation, and bubble-induced turbulence occurring during bubble floating process. So, some new and important inclusion transport mechanisms and phenomena have been presented. The CFD-PBM model was used to predict successfully the inclusion transport, collision growth and removal behavior in the molten steel, which enriches the inclusions removal theory of ladle refining. The CFD-SRM coupled model was used to accurately describe the slag-metal reaction and desulfurization behavior in a gas-stirred ladle, and the effect of the different content of compositions in synthetic slag and liquid steel, arrangement of bottom blowing tuyeres on the slag-metal reactions and desulfurization efficiency were discussed and clarified. For steel continuous casting, as the heat flow model from the solidified shell to the copper plate of mold was coupled with the thermo/mechanical model of the solidified shell, distributions of mold flux and air gap both along circumference and height directions of the mold were successfully predicted, while founded theoretical backgrounds for designing new mold with inner convex surface and controlling the surface corner crack of micro-alloyed steel. The coupled simulation between flow and electromagnetic fields in mold revealed the flow behavior of molten steel with electromagnetic stirring or braking, the fluctuation characteristic of the slag-steel interface and the distribution characteristic of inclusions in the strand. Based on the volume averaged method, multi-field and multi-phase solidification model successfully clarified the formation mechanism of macro-segregation in continuously cast strand and quantitatively predicted central/centerline segregation indexes in the strand under different casting conditions. In addition, the numerical simulation of the evolution of solidification structure of the continuously cast strand mainly focused on the as-cast grain, and its extension to the dendrite structure needed further more endeavors. Generally speaking, the numerical simulation in steelmaking-continuous casting process is moving towards coupling multi-physical/chemistry phenomena and multi-fields and gradually transits to the microscopic scale.     

中间包微气泡冶金技术发展

中间包中生成微小气泡可显著促进夹杂物上浮去除。对中间包微气泡精炼技术进行了分析总结,并针对研究较为深入的长水口吹氩技术相关文献进行了详细分析。结果表明,利用中间包中钢液湍动能破碎气泡可形成高效去除夹杂物技术,一些新技术正在研发过程中,长水口吹氩技术具有良好前景;“冷钢片沾钢”工业试验表明,中间包长水口吹氩可在中间包钢液中生成弥散细小氩气泡,生成的绝大部分氩气泡尺寸小于2 mm;长水口吹氩生成微小气泡的过程可分为气泡在长水口壁孔脱附和脱附气泡在湍急钢流中被剪碎成微小气泡两个阶段,其中钢液湍动能对氩气泡的剪切破碎作用十分明显;长水口吹氩技术水模型研究较多,数值模拟研究相对较少,工业试验研究才刚刚开始,有待更进一步的深入研究。     

浇包内温度场的有限元数值模拟

根据实验室双辊铸轧铝薄带的实际条件。针对浇包在充满铝液至开浇前的停置过程中的温度变化问题．采用二维能量传输的数学模型和ANSYS有限元分析软件。计算了不同预热温度、不同保温方式下浇包内温度场随时间的变化规律。为确定合适的开浇时间提供了理论依据。     

ANSYS软件在连铸过程中的应用

连铸冶金过程非常复杂且伴随着高温,运用人眼法、物理试验法等传统的研究方法难以观测,数值模拟技术恰能弥补这一不足。有限元软件ANSYS以准确、安全、可靠等优点被广泛应用到连铸上。主要介绍了ANSYS在连铸中的研究现状,详细讨论了ANSYS在连铸钢包、中间包、结晶器、二冷区、空冷区中的应用。最后,为了使ANSYS与连铸更好地结合,指出了ANSYS在连铸中的发展趋势。     

150 t钢包底吹氩气物理模拟

为评估国内某钢厂150 t钢包底吹氩工艺中供气流量、比例和底吹元件类型对精炼工艺的影响,建立了1:4物理模拟模型,研究了总供气量、供气方式和底吹元件类型对混匀时间的影响。结果表明,随总供气量的增加,使用两种类型底吹元件的钢包混匀时间下降,在小气量下使用弥散型底吹元件混匀时间小于狭缝型,较大气量下两者相反,且使用狭缝型底吹元件混匀时间受供气方式影响更大。试验条件下离钢包中心较远的底吹位置使用较大的底吹流量有利于混匀。     

FLUID DYNAMICS IN A GAS-STIRRED LADLE——A Separated Flow Model with Stochastical Trajectories

A separated flow model with stochastical trajectories has been developed to describe the fluidflow in a bubble stirred ladle.The bubble dispersion,turbulent characteristics and gas-liquidinteractions can be predicted by this mathematical model.The bubble flow as a dispersedphase is treated in a Lagrangian frame of reference and the analysis of the turbulent flow forliquid phase is conducted in a Eulerian field.The interactions between bubbles and liquidphases are considered as a bubble source term in the control equation for a continuous phase.The Monte Carlo sampling method is used to determine the bubble trajectories.The homoge-neous flow model is also taken into consideration so that it can be compared with the sepa-rated flow model.Numerical predictions using a water model of a ladle show that the pre-dicted results of the separated flow model agree satisfactorily with the experimental results,but the prediction of the homogeneous flow model are not in good agreement with the experi-mental results.