于海岐朱苗勇
金属学报
建立了描述圆坯连铸结晶器电磁搅拌过程的三维数学模型. 采用有限元和有限体积结合的方法求解Maxwell方程组和湍流Navier-Stokes方程, 分析了结晶器电磁搅拌过程的磁场、流场、温度场和夹杂物轨迹特征, 并考虑了励磁电磁强度和频率的影响. 研究表明, 磁场模拟结果与现场实测数据一致, 电磁力在圆坯水平截面上呈周向分布. 钢液在结晶器纵截面内形成两对回流区, 且在水平截面内旋转流动; 过热钢液滞留在结晶器上部区域, 铸坯芯部温度迅速降低, 凝固前沿温度梯度提高; 大部分夹杂物积聚到结晶器上部区域旋转运动. 励磁电流强度和频率对结晶器内钢液的流动、温度分布及夹杂物运动均有明显影响.
关键词:
圆坯结晶器
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electromagnetic stirring (EMS)
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electromagnetic field
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flow field
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Temperature field
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Inclusion
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numerical simulation
QU Ying YANG Jian XU Baomei University of Science and Technology Beijing
,
Beijing
,
China
金属学报(英文版)
By use of the two-component LDA and high speed camera,the water model of the flow field in metal bath under molten slag layer has been tested.On the basis of experimental results,the flow boundary conditions of liquid metal at the slag-metal interface of a gas injecting bath were deduced.The flow field and the turbulent parameters of the metal bath covered with slag were solved by the vorticity-stream function method.The results reveal that the flow velocity, turbulent energy and circulating rate of the melt under slag are lower than that of without slagcover.Another one “dead zone” of the lowest turbulent energy is formed in the top layer under cover of slag near the ladle linning.
关键词:
flow field
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null
,
null
,
null
J. Li
,
W. Liu
,
Y.Q. Lai
,
null
,
null
金属学报(英文版)
Two full 3D steady mathematical models are developed by finite element method (FEM) to calculate coupled physics fields: the electro-magnetic model is built and solved first and so is the fluid motion model with the acquired electromagnetic force as source body forces in Navier-Stokes equations. Effects caused by the ferromagnetic shell, busbar system around, and open boundary problem as well as inside induced current were considered in terms of the magnetic field. Furthermore, a new modeling method is found to set up solid models and then mesh them entirely with so-called structuralized grids, namely hex-mesh. Examples of 75kA prebaked cell with two kinds of busbar arrangements are presented. Results agree with those disclosed in the literature and confirm that the coupled simulation is valid. It is also concluded that the usage of these models facilitates the consistent analysis of the electric field to magnetic field and then flow motion to the greater extent, local distributions of current density and magnetic flux density are very much dependent on the cell structure, the steel shell is a shield to reduce the magnetic field and flow pattern is two dimensional in the main body of the metal pad.
关键词:
coupled simulation
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null
,
null
,
null
,
null
HE Youduo Baotou Institute of Iron and Steel Technology
,
Baotou
,
ChinaY.SAHAI The Ohio State University
,
USA HE Youduo
,
Professor
,
Department of Metallurgy
,
Baotou Institute of Iron and Steel Technology
,
Baotou
,
China
金属学报(英文版)
The influence of some factors on velocity field in continuous casting tundishes has been veri- fied by means of computer simulation.These factors are tundish wall inclination;the dimensionless geometric size of tundish,the double inclined wall tundish;the dimension and location of weir and dam.
关键词:
continuous casting tundish
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null
冯学武
,
金焱
,
李洋
,
程常桂
,
常正昇
,
金业磊
钢铁钒钛
doi:10.7513/j.issn.1004-7638.2015.05.023
为探究炉缸炉底在正常侵蚀的情况下和出现挂渣之后侵蚀的情况下炉缸内铁水流场的区别.以流体力学理论基础,建立了炉缸炉底在侵蚀前后铁水流场的三维数学模型和炉缸内生成结渣之后铁水流动对炉缸炉底的侵蚀情况的三维数学模型.利用CFX软件,研究不同时期炉缸炉底的速度矢量和不同位置的流线.结果表明,生成挂渣前后炉缸出现环流现象,但是由于挂渣粘附在炉缸上,对炉缸有一定的保护作用,同时炉缸内出现挂渣之后减小了炉缸的内部构造,使铁水流出出铁口的速度加快.在生产中可利用生成挂渣,加快出铁速度,同时依靠挂渣的保护作用,延长高炉炉缸的使用年限.
关键词:
高炉
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炉缸
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炉底
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剪切应力
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流场
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挂渣
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死焦柱
王杰杰
,
陈伟
钢铁钒钛
doi:10.7513/j.issn.1004-7638.2016.03.020
采用数值模拟软件Fluent建立了一个瞬态的三维数学模型,对100 t氧气顶吹转炉流场进行数值模拟.通过改变氧枪枪位和氧枪喷孔夹角,得出相应的冲击深度和冲击面积以及熔池内部速度分布.结果表明,在相同的条件下,随喷吹枪位的升高,射流形成的钢液凹坑直径变大,而冲击深度变小;随喷孔夹角的增大,射流冲击直径变大,而冲击深度减小.低枪位有利于增大熔池上层钢液流速,高枪位利于促进熔池下部钢液流动;喷孔夹角增大利于增大熔池表层高速区面积,但熔池中心底部低速区面积也随之增大.
关键词:
转炉
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三相流
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流场
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氧枪
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枪位
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喷孔夹角
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数值模拟
张兴中
,
任素波
,
周超
,
刘晶晶
,
白明华
钢铁
doi:10.13228/j.boyuan.issn0449-749x.20150279
为降低700 mm×700 mm特大方坯连铸机高度，保证大方坯的顺利生产，提出一种内置冷却器的结晶器技术，即“回”字形结晶器。利用计算流体动力学（CFD）软件FLUENT对此结晶器内钢水流场及温度进行模拟，对无内冷却器偏转水口注流结晶器、无内冷却器四孔水口注流结晶器内流场及“回”字形注流结晶器流场、温度场进行研究，表明“回”字形结晶器可以形成水平旋流、均匀钢水成分及坯壳生长、降低钢水冲击深度，部分达到电磁搅拌（M-EMS）的冶金效果，温度场模拟结果表明出口坯壳厚度达到49 mm，满足工艺要求。
关键词:
大方坯
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内冷却器
,
结晶器
,
流场
,
温度场
郑建新
,
郝婉君
表面技术
doi:10.16490/j.cnki.issn.1001-3660.2015.12.012
目的 真空度直接影响着真空冷喷涂时气体流动特性和颗粒撞击速度,研究真空度对气体和颗粒流动特性的影响. 方法 确定真空冷喷涂系统结构,采用FLUENT软件进行真空冷喷涂气固两相流研究,通过数值模拟研究真空度对流场和颗粒撞击速度的影响,并研究相同压力比下的气固两相流特性.结果 当入口压力一定时,喷管内的气体轴线速度、密度和温度与环境压力大小无关;而在射流区,环境压力越小,则气体轴线速度波动越小、密度越低,但到达基板后的气体温度均接近喷管入口温度. 环境压力对大粒径颗粒的撞击速度影响较大,颗粒撞击速度随环境压力增大而先增后减,最佳环境压力可根据气相云图和气体密度来确定. 当进出口压力比相同时,喷管内和射流区域内的气相速度云图基本相同,气体轴线速度曲线基本重合,而基板前的颗粒速度不同,此时环境压力越低,颗粒速度越高,越有利于形成涂层. 结论 采用计算流体动力学分析方法厘清了真空度对真空冷喷涂气固两相流的影响,为涂层制备奠定了理论基础.
关键词:
真空冷喷涂
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气固两相流
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真空度
,
流场
,
颗粒速度
,
数值研究
潘刚
,
范勇
,
彭迎彬
,
武文斐
钢铁钒钛
doi:10.7513/j.issn.1004-7638.2015.06.019
基于EMMS模型、耦合双流体模型对内置隔板流化床内气固两相流动规律进行研究,包含流化床内气固两相的速度分布规律、固相颗粒体积分数分布规律、粒径对固相颗粒体积分数分布的影响规律等内容.结果表明:流化床内存在固体颗粒的返混现象,多个隔板的存在增强流化床内的返混现象;局部固相颗粒体积分数较高,表明固体颗粒发生了团聚现象;固相颗粒体积分数呈现出"上稀下浓"和,"核稀边密"的分布规律,且在高度方向的变化规律呈现出"S"曲线;随着颗粒粒径的减小,被气体携带进入高度h=0.1～0.4 m区域的固体颗粒增多.研究结果可为深入理解内置隔板流化床内磁化焙烧过程中气固两相流动规律提供理论指导.
关键词:
流化床
,
内置隔板
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流场分布
,
EMMS模型
,
数值模拟
