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
,
electromagnetic stirring (EMS)
,
electromagnetic field
,
flow field
,
Temperature field
,
Inclusion
,
numerical simulation
王芳李宝宽
金属学报
doi:10.3724/SP.J.1037.2010.00080
以电渣重熔工艺中电极、渣池和钢锭为研究对象, 建立了能够考虑集肤效应的三维谐波电磁场有限元模型, 采用Maxwell方程、Lorentz定律和Joule定律分析了渣、钢锭和电极的磁场、电磁力、电流密度和Joule热功率密度的分布. 模拟结果与测量的电渣重熔系统外部空气的磁感应强度吻合良好, 证明了本模型和计算过程的可靠性. 计算结果表明: 在电极和钢锭内, 电流主要集中在外表面, 电流沿轴向方向; 在渣池内, 由于渣的电导率低, 电流分布发生改变, 主要集中在电极端头处; 电磁力的最大值出现在接近渣池上表面渣内的电极附近; 而Joule热的最大值是在电极底部与渣的交界处; 当频率大于35 Hz时, 电极和钢锭内都出现了涡流; 当电极浸入深度增大或渣层的厚度减小时, 渣池中Joule热的最大值增大.
关键词:
电渣重熔
,
electromagnetic field
,
Joule heating
,
numerical simulation
GE Yunlong YANG Yuansheng JIAO Yuning HU Zhuangqi Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
ChinaGAO Yunyan JIA Guanglin Northeast University of Technology
,
Shenyang
,
China associate professor
,
Institute of Low Energy Nuclear Physics
,
Beijing Normal University
,
Beijing
,
100875
,
China
金属学报(英文版)
A new technique of centrifugal casting under electromagnetic field was firstly proposed and investigated.Taking a heat resisting alloy steel 25Cr20Ni and an Al-Cu alloy as examples,products,though their length,diameter and wall thickness are varied,re- vealed so superior macrostructures that the mechanical properties are much improved in comparison with conventional centrifugal casting.
关键词:
electromagnetic field
,
null
,
null
,
null
金百刚
,
王强
,
刘岩
,
崔大伟
,
赫冀成
金属学报
通过有限元数值模拟，讨论了两段式结晶器上半段长度、感应线圈的位置、液面位置对结晶器内部磁场的影响规律，并深入分析了两段式结晶器整个系统的电磁场分布规律。结果表明：两段式结晶器上半段越长，其透磁效果越好；线圈位置越靠上，结晶器透磁效果越好；液面位于线圈中心偏上20 mm时，内部磁场的作用效果最佳。在本研究条件下，两段式结晶器透磁效果良好，磁感应强度主要集中在结晶器上半段钢液弯月面区域。纵向磁场在结晶器上半段高度范围内逐渐增强，在结晶器下半段高度范围迅速衰减；周向磁场在钢液表面均匀分布；径向磁场由钢液表面向内部逐渐衰减。通过两段式结晶器与切缝式结晶器的比较发现，两段式结晶器内部磁场分布更均匀，易于在生产中实现。
关键词:
软接触电磁连铸
,
two-stage slitless mold
,
electromagnetic field
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
,
null
,
null
,
null
,
null
Z.D. Qian
,
B.W. Li
,
E.G. Wang
金属学报(英文版)
A new treatment for interface of metal and dielectric in finite-difference time domain(FDTD) method was presented, further how and why this treatment should be as itis was explained. The FDTD method was developed to compute the low-frequencyelectromagnetic fields in the metal instead of the traditional high-frequency ones as itwas originally proposed. The computational results agreed well with the experimentalones.
关键词:
FDTD method
,
null
,
null
,
null
王堂玺
,
李享成
,
平振丰
耐火材料
doi:10.3969/j.issn.1001-1935.2014.06.007
为了探索MgO－C砖在电磁搅拌、电弧炉和感应炉等电磁场环境下使用时的抗渣侵蚀性，采用w （C ）分别为6％、14％的MgO－C砖和m（CaO）／m（SiO2）＝3．5的炉渣在中频感应炉中进行抗熔渣侵蚀试验，并对渣蚀后试样进行了XRD和SEM、EDAX分析。结果表明：在电磁场环境下，w（C）＝6％的镁碳砖渣蚀后低熔点相为镁黄长石，w（C）＝14％的镁碳砖渣蚀后低熔点相为黄长石。镁碳砖渣蚀过程中，w（C）＝6％的镁碳砖中镁砂未完全形成镁铁（锰）固溶体或镁铁尖晶石即剥落于熔渣中；而w（C）＝14％的镁碳砖中镁砂形成镁铁（锰）固溶体或镁铁尖晶石后剥落于熔渣中；在渣蚀后镁碳砖过渡层中，电磁场促进了Al2 O3、MnO、FeO、Fe2 O3的渗透，生成镁铁（锰）固溶体、镁铁尖晶石、镁铝尖晶石或金属单质，w（C）＝14％的镁碳砖渗透较弱，生成的固溶体或尖晶石较少，易剥落于熔渣中。
关键词:
电磁场
,
镁碳砖
,
碳含量
,
侵蚀
,
高碱度渣
张春华
,
于海
,
张冬华
硅酸盐通报
为了提高聚合硫酸铁的混凝性能,增强对污水的去除能力.利用自制交流变频磁化装置,对聚合硫酸铁溶液进行磁化处理,以铁盐水解形态Feb为指标,交流变频电磁场的频率、电压、电流及磁化时间为实验因素,对电磁场作用下的聚合硫酸铁溶液进行形态分析,并与非磁化的PFS溶液进行对比;以高炉煤气洗涤水为实验水样,通过混凝试验对比聚合硫酸铁溶液磁化前后的出水浊度及COD值.研究结果表明:电磁场作用下的聚合硫酸铁溶液的形态分布发生了变化,与非磁化相比,Feb百分比含量增加了1倍,Fec百分比含量减少了1/3,且当频率为300 Hz、电压为100 V、电流为0.8A、磁化时间为2 min时Feb的百分比含量达到最大;电磁场能明显提高聚合硫酸铁的混凝性能,与非磁化的聚合硫酸铁溶液相比出水浊度与COD值降为原来的一半,投药量节省了1倍.
关键词:
聚合硫酸铁
,
电磁场
,
形态分布
,
水处理
,
出水浊度
