不锈钢板坯连铸非对称T型中间包和结晶器的数学物理模拟
文献类型：学位论文
| 作者 | 刘松霞 |
| 学位类别 | 硕士 |
| 答辩日期 | 2008-05-27 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 过程工程研究所 |
| 导师 | 杨学民 |
| 关键词 | 非对称T型中间包 板坯连铸结晶器 流场 温度场 水力学模拟 数值模拟 正交实验 极差分析 |
| 其他题名 | Hydrodynamic and Mathematical Simulations of an Asymmetrical T-type Tundish and a Stainless Steel Slab Continuous Casting Mold |
| 学位专业 | 化学工程 |
| 中文摘要 | 钢铁工业是国民经济发展的基础工业，随着连续铸钢技术的发展，铸坯质量要求的不断提高，对于钢液洁净度的要求也越来越高。中间包、结晶器内钢液的流动状态对延长钢液在中间包内的停留时间，减少死区，改善夹杂物的上浮与排出，减少钢液表面卷渣和二次氧化，稳定钢液温度及化学成分等都有重要作用，直接影响到连铸坯的质量。 针对山西太钢二炼钢厂不锈钢铸坯的表面夹杂与皮下夹杂含量较高，造成冷轧不锈钢板的降级使用或报废问题，本文运用水力学模型进行正交和单因素实验，同时运用流体力学软件FLUENT进行等温和非等温条件下的数值模拟计算，对该厂连铸单流非对称T型中间包和板坯结晶器的相关结构参数和工艺参数对流场及温度场的影响进行了系统研究，对于提高不锈钢板坯质量具有一定的理论意义和重要的应用背景。 中间包的水模和数模研究结果表明：(1)中间包原T0工况设计的内部控流装置不够合理，参数优化后的T4、T7、T8、T12、T14工况和坝底开圆型孔的RST1和拱门型孔的AST5工况流场死区减少、活塞区增加、停留时间延长，且温度场得到了进一步优化；(2) 证明了为减少换包时中间包内残钢量而实施坝底开孔方案的可行性，其中AST5在坝底两侧对称开2个高度为30mm、半圆的半径为50mm的拱门型孔，RST1在坝底左侧开一个半径为70mm的圆型孔，所有孔中心距离坝中心线205mm；(3) 极差分析得出对于中间包流场影响能力的大小次序为小墙高度-坝高-堰深-水口浸入深度-堰坝间距；随小墙高度增加、坝高增加、堰加深、水口深度增加，滞止时间和平均停留时间延长、活塞区增大、死区减小；(4) 通过等温和非等温数值计算对比证明中间包壁面及表面散热对流场的影响不可忽略，数模计算中间包进出口温差4.4K，最大温差10K。 结晶器的水模和数模研究结果表明：(1) 结晶器的浸入式水口倾角和拉速对液面波动影响较大，水口浸入深度对冲击深度影响较大；(2) 水口倾角越上倾、水口浸入深度越小、拉速越大、结晶器断面越小，则越容易引起较大的液面波动，造成保护渣卷入；(3) 适宜的水口倾角为向上100左右，水口浸入深度120-143mm为宜，相同拉速下可采用大断面1380mm×220mm。 |
| 英文摘要 | With the development of the continuous casting technology, the urgent requirements of improving slab quality and decreasing mini-size nonmetallic inclusions have attracted a lot of attention in the past decades. It is well known that reasonable flow pattern of molten steel in tundish and mold during continuous casting process can play significant roles in prolongation of molten steel residence time, reduction of dead zone, removal of nonmetallic inclusions, reduction of entrapped top slag or air, and stabilization of melt temperature and composition, and thus it has important effects on slab quality. To further remove mini-size nonmetallic inclusions in stainless steel slab and reduce degraded or scrapped products at No.2 Steelmaking Plant of Shanxi Taigang Stainless Steel Company Limited, the 1:3 and 1:1.5 reduced scale hydrodynamic models for an asymmetrical T-type single-strand tundish and slab mold, respectively, coupled with mathematical simulation have been applied to investigate flow field of molten stainless steel in this thesis. The orthogonal tests were carried out in the hydrodynamic modelling, and the results were analyzed by the range analysis, meanwhile, the Computational Fluid Dynamics (CFD) software FLUENT was applied in mathematical simulation. According to results from hydrodynamic and mathematical simulation, the optimal structural and technological parameters for both the tundish and the mold have been suggested. The results of hydrodynamic and mathematical simulation of the tundish indicate that: (1) The original designed T0 case tundish has unreasonable flow-control device parameters, the optimized cases of T4, T7, T8, T12, T14, RST1 with round hole and AST5 with arch holes can improve dispersed plug zone, reduce dead zone, and prolong the residence time effectively, as well as optimize the temperature profile. (2) Opening holes at the bottom of dam can effectively reduce the remained stainless molten steel in tundish when changing ladle; while the shape, size and number of holes will influence the flow field in tundish and too big or too many holes will cause short circuit to some extent, so the integrated parameters of holes need deciding. (3) The order of importance of structural parameters on flow field of molten stainless steel in the tundish is height for low-wall of turbulence inhibitor--dam height--weir depth--submerged depth of ladle shroud--distance between dam and weir; as the increase of low-wall height, dam height, weir depth, and submerged depth of ladle shroud, the residence time and break through time is extended, dispersed plug zone is prolonged, and dead zone is decreased. (4) Heat losses around the tundish must be considered in order to accurately simulate the streamline, velocity vector field and temperature profile. The calculated temperature drop of steel between inlet and outlet of the tundish is about 4.4K; the maximum temperature drop in tundish is about 10K. The hydrodynamic and mathematical simulation results of the mold indicate that: (1) The port angle of submerged entry nozzle (SEN) and casting speed effect the surface fluctuation of molten steel greatly, and the submergence depth of SEN can effect the striking depth greatly. (2) The upper port angle, the shorter submergence depth of SEN, the higher casting speed and the smaller mold cross section can cause larger surface fluctuation and more entrapped top slag. (3) The reasonable port angle is +100, and submergence depth of SEN 120-143mm. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 165 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1213]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 刘松霞. 不锈钢板坯连铸非对称T型中间包和结晶器的数学物理模拟[D]. 过程工程研究所. 中国科学院过程工程研究所. 2008. |
入库方式： OAI收割
来源：过程工程研究所
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