共查询到18条相似文献,搜索用时 93 毫秒
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板坯连铸中间包内夹杂物去除的数值模拟 总被引:1,自引:0,他引:1
以某厂50tT型2流中间包为研究对象,利用大型商业软件ANSYS CFX10.0建立了三维有限体积模型,采用多相流模型对中间包内钢液的流动特性、温度分布与夹杂物去除规律进行了数值模拟,重点研究了不同堰-坝组合方式、湍流抑制器形状、拉速、夹杂物粒径等工艺参数对中间包内钢水平均停留时间、夹杂物上浮率的影响。结果表明:湍流抑制器对夹杂物的上浮去除影响不大;随着夹杂物粒径的增大,夹杂物的上浮率迅速增大;20μm以下的夹杂物则很难在中间包内上浮去除;随着拉速的增大,夹杂物的上浮率是不断减小的;采用堰A=300cm、坝B=400cm、方形瓦楞湍流抑制器、过滤器组合式控流装置时夹杂物的上浮去除效果最好。 相似文献
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连铸中间包钢水流动及夹杂物运动的数值模拟 总被引:1,自引:0,他引:1
本文对某厂的连铸中间包两种不同流动控制条件下的钢水流动进行了三维数学模拟.湍流的模拟采用κ-ε双方程模型.通过分析夹杂物所受力的平衡建立了夹杂物运动方程,主要考虑了流体的拖曳力和来自于夹杂物和钢水之间密度差的上浮力,并通过随机运动模型模拟了湍流脉动对夹杂物运动的影响,计算了多粒径夹杂物的三维运动及其轨迹.模拟结果表明,如果挡墙上方有钢水流过,将会在挡墙上方附近产生较大的流速和强烈的涡流,并且钢水从不同方向向一个界面(界线)流动,导致不同流向的钢流相互碰撞,所有这些都将导致卷渣和重新卷入夹杂物.因此,钢水液面大于挡墙高度对夹杂物的去除不利.采用全挡墙(即挡墙与中间包钢水高度一致,挡墙上合理布置出孔)的条件下产生的钢水流动方式有利于夹杂物的去除.计算表明在挡墙合理布置出孔的情况下,如果挡墙高度和钢水深度都是1000mm时,50μm的夹杂物可以安全去除32%;而当钢水液面高度为780mm,挡墙高度为660mm时,50μm夹杂物仅可以安全去除13%.为了更有效的去除夹杂物,抑制涡流形成引发的渣乳化,引起卷渣以及重新卷入已经去除到顶渣的夹杂物,中间包钢水深度应该大于1000mm. 相似文献
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以25t中间包为原型,通过实验相似比λ=1:2.3的水模型,分析了4流近似T型中间包3种挡墙形式包内流场及夹杂物去除。结果表明,原挡墙控流下的中间包同一侧两流之间的流体流动特性差异很大,与内侧相比,外侧流的最短停留时间和峰值时间长、死区体积大,造成中间包内钢液温度不均匀,夹杂物不能有效地上浮去除;U-型挡墙能延长峰值时间,但是最短停留时间短,死区比例较大;采用Y-型挡墙可以有效地改变中间包内流场分布,促进夹杂物上浮。30CrMo钢工业试验表明,采用Y-型挡墙钢中大型夹杂物较原用挡墙降低16.9%。 相似文献
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以某钢厂的八流连铸中间包为研究对象,采用数值模拟方法对不同控流结构中间包内钢液流场进行了研究,并通过水模型实验和工业生产进行验证。模拟结果表明:ASF中间包内的挡墙和湍流器能够明显改善钢液的流动状态和温度分布,加上双坝后效果更佳,钢液的流动存在4个环流区,不仅增加了钢液的混合程度,而且中间包内钢液的温度分布更均匀且低温区较少。水模试验表明在空包中加入湍流器和挡墙能明显改善各流流动特性的一致性,且在其基础上加入双坝能进一步改善钢液的流动特性,与数值模拟结果一致,此外,工业生产也完全达到预期效果。 相似文献
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Fluid flow and inclusion removal in continuous casting tundish 总被引:10,自引:0,他引:10
Lifeng Zhang Shoji Taniguchi Kaike Cai 《Metallurgical and Materials Transactions B》2000,31(2):253-266
Three-dimensional fluid flow in continuous casting tundishes with and without flow control devices is first studied. The results
indicate that flow control devices are effective to control the strong stirring energy within the inlet zone, and other zones
are with much uniform streamline. By dividing tundish into two zones with different inclusion removal mechanisms the inclusion
removal is calculated. Three modes of inclusion removal from molten steel in the tundish, i.e., flotation to the free surface, collision and coalescence of inclusions to form larger ones, and adhesion to the lining solid
surfaces, are taken into account. The Brownian collision, Stokes collision, and turbulent collision are examined and discussed.
The suitable coagulation coefficient is discussed, and a value of 0.18 is derived. Calculation results indicate that, besides
flotation, collision of inclusion and adhesion to the lining solid surfaces are also important ways for inclusion removal
from molten steel in tundish especially for the smaller inclusions. The flotation removal holds 49.5 pct, and the adhesion
removal holds 29.5 pct for the tundish with flow control devices; the collision effect is reflected in improving flotation
and adhesion. Finally, industrial experiment data are used to verify the inclusion removal model. 相似文献
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Effects of continuous casting process parameters on carbon segregation degree of 38CrMoAl steel big round billet 总被引:2,自引:0,他引:2
The effects of continuous casting process parameters (superheat degree, casting speed and F- EMS) on the carbon segregation of round billet with diameter 600mm of 38CrMoAl steel were investigated by industrial experiments and numerical simulations. The results show that the equiaxed crystal rate and solidification structure both affect the carbon segregation. When the superheat is low, shrinkage tends to occur, and the shrinkage is often accompanied by severe segregation. When the superheat is high, the equiaxed grain ratio is lower, carbon segregation is also severer, so the superheat degree is controlled at 30??. With the increasing of casting speed?? it can obviously spur the growth of columnar crystals and formation of central pipe; both columnar crystals and central pipe are the major cause of segregation, so the suitable casting speed is 0. 19m/min. Final electromagnetic stirring has the effect of uniform liquid steel composition and temperature, which increases the density of solidification structure, and reduces the central shrinkage hole, thereby reducing carbon segregation, but the electromagnetic stirring effect is greatly affected by the installation position. Based on comprehensive consideration of the production and quality in practical production, the suitable process parameters are established: the optimal superheat is 30??, casting speed is 0. 28m/min, the combination of electromagnetic stirring is M- EMS+S- EMS+F- EMS, and the corresponding electromagnetic stirring parameters are M- EMS of 101A/2Hz??S- EMS of 200A/8Hz??F- ME of 900A/8Hz. Under the above process conditions, it will be more reasonable for the F- EMS installation position to move 0. 4-0. 5m toward the meniscus. 相似文献
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在Euler-Lagrange框架下,基于应用分形理论对凝聚态Al2O3夹杂物形貌结构进行定量分析的基础上,数值模拟研究了连铸中间包钢液中不同形貌凝聚态Al2O3夹杂物的运动行为.研究发现中间包钢液流场和夹杂物形貌尺寸共同影响夹杂物在钢液中的运动行为.随着尺寸的变大,簇群状和致密球形两种形貌Al2O3夹杂物上浮去除率都逐渐增加.在相同尺寸下,簇群状Al2O3夹杂物上浮去除率比致密球形Al2O3夹杂物低;随着尺寸的增加,簇群状Al2O3夹杂物上浮去除率相比于同尺寸致密球形Al2O3夹杂物降低得就越多.计算结果显示,与同尺寸的致密球形Al2O3夹杂物相比,直径为20、40、60和80μm的簇群状Al2O3夹杂物上浮去除率分别降低了4.8%、5.7%、6.4%和12.5%. 相似文献
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