Effect of electromagnetic stirring in extra-large billet on the flow field and temperature field
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摘要: 以某厂断面为410 mm × 530 mm的特大方坯结晶器为原型，利用ANSYS有限元软件建立三维数值模型，研究电磁搅拌对结晶器流场及温度场的影响。施加电磁搅拌后，钢液受到径向电磁力，液面呈现旋转流动趋势。结晶器内钢液最大切向速度随着电流的增加而增大，随着频率的增加而减小。电磁搅拌的电流大小由0 增加到500 A时，液面波动由1.21 mm增加到4.35 mm。电磁搅拌能够使钢水的高温区局限于连铸结晶器上部，钢水温度更加均匀。同时钢液的水平旋流能够抑制初生坯壳的生长，降低坯壳的生长速度，使结晶器出口处坯壳厚度变薄。综合分析，该厂在实际生产时合理的电磁搅拌的电流大小应为400 A，频率为1.5 Hz，此时钢渣液面波动约为2.73 mm，温度场较为均匀。Abstract: As the “heart” of continuous caster, the flow field of mold directly affects the quality of the slab. For a billet caster, in-mold electromagnetic stirring (M-EMS), as its necessary configuration, can improve the flow field in the mold, homogenize the liquid steel temperature, improve segregation, and improve the slab quality. This paper utilized a 410 mm × 530 mm large billet caster in a factory, which is one of the largest section casters in China. Based on it, a three-dimensional numerical model was established using the ANSYS finite element software to study the influence of electromagnetic stirring on the flow field, liquid level fluctuation, and temperature field of the mold. After electromagnetic stirring was applied, the liquid steel was subjected to a radial electromagnetic force, and the liquid surface shows a rotating flow trend. The maximum tangential velocity of molten steel increases with the increase of current and decreases with the increase of frequency. When the current of electromagnetic stirring increases from 0 A to 500 A, the fluctuation of the liquid level increases from 1.21 mm to 4.35 mm. The maximum tangential velocity of the electromagnetic stirring center increases from 0.02 m∙s−1 to 0.21 m∙s−1. Electromagnetic stirring can restrain the impact of the high-temperature jet from the nozzle, move the high-temperature zone of molten steel upward, and make the temperature of molten steel more uniform. Under the action of a radial electromagnetic force, the horizontal swirl of liquid steel can inhibit the growth of the primary shell, reduce the growth rate of the shell, and reduce the thickness of the shell out of the mold by about 2.3 mm. The comprehensive analysis shows that the reasonable current of electromagnetic stirring is 400 A and the frequency is 1.5 Hz. At this time, the fluctuation of the slag level is about 2.73 mm, and the temperature field is relatively uniform.
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Key words:
- extra-large boom /
- electromagnetic stirring /
- flow field /
- temperature field /
- numerical simulation
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图 1 结晶器（a）和水口（b）的网格划分示意图
Figure 1. Meshed computational model equipped with (a) a mold chamfer and (b) a four-port submerged entry nozzle (SEN)
图 2 电磁搅拌装置图（a）和安装示意图（b）
Figure 2. (a) Schematic illustration of the mold electromagnetic stirring(M-EMS) and (b) its install location
图 3 结晶器中心轴向线电磁搅拌强度测量值和计算值对比
Figure 3. Comparison of the calculated and measured magnetic flux density in M-EMS
图 4 无电磁搅拌（a）和施加电磁搅拌（b）情况下结晶器流场速度分布图和流线图
Figure 4. Velocity contour in the upper part of the mold (a) without EMS and (b) with EMS
图 5 电流强度对电磁搅拌中心速度的影响.（a）0 A；（b）300 A；（c）400 A；（d）500 A）
Figure 5. Effect of the current intensity on the velocity distribution of the stirring center: (a) 0 A; (b) 300 A; (c) 400 A; (d) 500 A
图 6 不同电流强度下电磁搅拌中心切向速度大小
Figure 6. Tangential velocity of the electromagnetic stirring center under different current intensities
图 7 钢渣界面速度大小分布云图.（a）无电磁搅拌；（b）施加电磁搅拌
Figure 7. Velocity distribution of the steel-slag interface (a) without EMS and (b) with EMS
图 8 不同电流强度下钢渣液面高度的分布.（a）0 A；（b）300 A；（c）400 A；（d）500 A）
Figure 8. Distribution of the liquid level of the steel-slag surface at different current intensities:（a）0 A;（b）300 A;（c）400 A;（d）500 A
图 9 电磁搅拌中轴线最大磁感应强度测量值
Figure 9. Actual measurement of the magnetic induction at the axis of electromagnetic stirring
图 10 频率对电磁搅拌中心切向速度的影响
Figure 10. Effect of the current frequency on the tangential velocity of the stirring center
图 11 水口冲击方向截面的温度分布和结晶器出口截面的液相分数分布.（a）0 A；（b）300 A；（c）400 A；（d）500 A）
Figure 11. Distribution of temperature in the impinging direction of the nozzle and the liquid fraction at the outlet of the mold: (a) 0 A ; (b) 300 A; (c) 400 A; (d) 500 A
图 12 坯壳厚度沿铸造方向的增长情况
Figure 12. Growth of the solidified shell thickness along the casting direction
表 1 模拟计算条件
Table 1. Simulation conditions
Parameters Value Cross section of bloom/(mm×mm) 410×530 Submerged entry nozzle Four-port Casting speed/（m·min−1） 0.43 Casting temperature /K 1790 Density of steel /（kg·m−3） 6970 Density of slag /（kg·m−3） 2500 Viscosity of steel /（kg·m−1·s−1） 0.00623 Liquidus temperature /K 1765 Solidus temperature /K 1698 Steel resistivity /（Ω·m） 1.4×10−6 Copper plate resistivity /（Ω·m） 1.7×10−8 Running current of M-EMS /A 200–600 Running frequency of M-EMS /Hz 1.5–3.5 Permeability of iron core
Permeability of steel1000
1
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参考文献
[1] Cai K K. Continuous Casting Mold. Beijing: Metallurgical Industry Press, 2008蔡开科. 连铸结晶器. 北京: 冶金工业出版社, 2008 [2] Spitzer K H, Dubke M, Schwerdtfeger K. Rotational electromagnetic stirring in continuous casting of round strands. Metall Trans B, 1986, 17(1): 119 doi: 10.1007/BF02670825 [3] Wu H J, Wei N, Bao Y P, et al. Effect of M-EMS on the solidification structure of a steel billet. Int J Miner Metall Mater, 2011, 18(2): 159 doi: 10.1007/s12613-011-0416-y [4] Ren B Z, Chen D F, Wang H D, et al. Numerical simulation of fluid flow and solidification in bloom continuous casting mould with electromagnetic stirring. Ironmak Steelmak, 2015, 42(6): 401 doi: 10.1179/1743281214Y.0000000240 [5] Wen Y M, Han Y S, Liu Q, et al. Optimization of multi-fields coupled molten steel behavior in bloom continuous casting. Iron Steel, 2018, 53(6): 53文艳梅, 韩延申, 刘青, 等. 大方坯结晶器内的多物理场模拟优化. 钢铁, 2018, 53(6):53 [6] Yu Y, Li B K, Yang G. Numerical modeling of flow fields in the continuous casting process of steel under electromagnetic stirring. J Univ Sci Technol Beijing, 2011, 33(2): 157于洋, 李宝宽, 杨刚. 钢连铸电磁搅拌工艺中流场的数值模拟. 北京科技大学学报, 2011, 33(2):157 [7] Maurya A, Jha P K. Influence of electromagnetic stirrer position on fluid flow and solidification in continuous casting mold. Appl Math Model, 2017, 48: 736 doi: 10.1016/j.apm.2017.02.029 [8] Wang W W, Zhang J Q, Chen S Q, et al. Effect of nozzle outlet angle on the fluid flow and level fluctuation in a bloom casting mould. J Univ Sci Technol Beijing, 2007, 29(8): 816 doi: 10.3321/j.issn:1001-053x.2007.08.015王维维, 张家泉, 陈素琼, 等. 水口侧孔倾角对大方坯结晶器流场和液面波动的影响. 北京科技大学学报, 2007, 29(8):816 doi: 10.3321/j.issn:1001-053x.2007.08.015 [9] Fang Q, Ni H W, Wang B, et al. Effects of EMS induced flow on solidification and solute transport in bloom mold. Metals, 2017, 7(3): 72 doi: 10.3390/met7030072 [10] Fang Q, Ni H W, Zhang H, et al. The effects of a submerged entry nozzle on flow and initial solidification in a continuous casting bloom mold with electromagnetic stirring. Metals, 2017, 7(4): 146 doi: 10.3390/met7040146 [11] He M L, Wang N, Chen M, et al. Physical and numerical simulation of the fluid flow and temperature distribution in bloom continuous casting mold. Steel Res Int, 2017, 88(9): 1600447 doi: 10.1002/srin.201600447 [12] Aboutalebi M M, Labrecque C, D'Amours J, et al. Angular Re-positioning of a five ported SEN versus EMS braking to stabilize flows at the upper slag-liquid steel interface. Steel Res Int, 2019, 90(3): 1800429 doi: 10.1002/srin.201800429 [13] Wang Y T, Yang Z G, Zhang X F, et al. Effects of electromagnetic stirring on the flow field and level fluctuation in bloom molds. J Univ Sci Technol Beijing, 2014, 36(10): 1354王亚涛, 杨振国, 张晓峰, 等. 电磁搅拌对大方坯结晶器流场和液面波动的影响. 北京科技大学学报, 2014, 36(10):1354 [14] Li F S, Chen W Q. Numerical simulation of flow field and temperature distribution in continuously cast rectangular billet mold. Shanghai Met, 2016, 38(3): 73 doi: 10.3969/j.issn.1001-7208.2016.03.015李凤善, 陈伟庆. 矩形坯连铸结晶器流场和温度场的数值模拟. 上海金属, 2016, 38(3):73 doi: 10.3969/j.issn.1001-7208.2016.03.015 [15] Li S X, Lan P, Tang H Y, et al. Study on the electromagnetic field, fluid flow, and solidification in a bloom continuous casting mold by numerical simulation. Steel Res Int, 2018, 89(12): 1800071 doi: 10.1002/srin.201800071 [16] LÜ M, Mi X Y, Zhang C H, et al. Effect of continuous-casting parameters on carbon segregation in SWRH82B high-carbon steel. Chin J Eng. 2020, 42(Suppl 1): 102吕明, 米小雨, 张朝晖, 等. 连铸工艺参数对SWRH82B高碳钢碳偏析的影响. 工程科学学报. 2020, 42(增刊): 102 [17] Wei N, Bao Y P, Wu H J, et al. Numerical simulation of 3-D electromagnetic field in a bloom continuous casting mold with electromagnetic stirring. J Univ Sci Technol Beijing, 2011, 33(6): 702魏宁, 包燕平, 吴华杰, 等. 大方坯连铸结晶器电磁搅拌三维电磁场的数值模拟. 北京科技大学学报, 2011, 33(6):702 [18] Maurya A, Jha P K. Two-phase analysis of interface level fluctuation in continuous casting mold with electromagnetic stirring. Int J Numer Methods Heat Fluid Flow, 2018, 28(9): 2036 doi: 10.1108/HFF-08-2017-0310 [19] Zhang J, Yang L, Han Z F, et al. Level fluctuation in continuous casting mold with electromagnetic stirring. J Iron Steel Res, 2016, 28(8): 17张静, 杨龙, 韩泽峰, 等. 电磁搅拌作用下连铸结晶器内液面波动行为. 钢铁研究学报, 2016, 28(8):17 [20] Li S X, Zhang X M, Li L, et al. Representation and effect of mushy zone coefficient on coupled flow and solidification simulation during continuous casting. Chin J Eng. 2019, 41(2): 199李少翔, 张晓萌, 李亮, 等. 连铸流动与凝固耦合模拟中糊状区系数的表征及影响. 工程科学学报. 2019, 41(2): 199 [21] Hu Q, Zhang S, Wang P, et al. Liquid level fluctuation and slag entrainment behavior in a bloom mold. China Metall, 2020, 30(6): 63胡群, 张硕, 王璞, 等. 大方坯结晶器内液面波动与卷渣行为. 中国冶金, 2020, 30(6):63 [22] An H H, Bao Y P, Wang M, et al. Optimization of in-mold electromagnetic stirring in continuously cast steel billet and bloom by electromagnetic torque detecting. // 2018 National Steelmaking Conference. Chengdu, 2018: 1安航航, 包燕平, 王敏, 等. 基于电磁力矩检测的方坯连铸结晶器电磁搅拌工艺参数优化//2018年(第二十届)全国炼钢学术会议. 成都, 2018: 1 [23] Mao B. Theory and Technology of Electromagnetic Stirring for Continuous Casting. Beijing: Metallurgical Industry Press, 2012毛斌. 连续铸钢用电磁搅拌的理论与技术. 北京: 冶金工业出版社, 2012 [24] Zhang J, Wang E G, Deng A Y, et al. Numerical simulation of flow field in bloom continuous casting mold with electromagnetic stirring. Adv Mater Res, 2010, 146-147: 272 doi: 10.4028/www.scientific.net/AMR.146-147.272 [25] Ren B Z, Chen D F, Wang H D, et al. Numerical simulation of fluid flow and solidification in bloom continuous casting mould with electromagnetic stirring. Ironmak Steelmak, 2015, 42(6): 401 doi: 10.1179/1743281214Y.0000000240 [26] Zhang W J, Luo S, Chen Y, et al. Numerical simulation of fluid flow, heat transfer, species transfer, and solidification in billet continuous casting mold with M-EMS. Metals, 2019, 9(1): 66 doi: 10.3390/met9010066 -
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