| 题名 | CO2溅渣护炉过程射流特性的模拟研究 |
| 作者 | 王文静 |
| 学位类别 | 硕士 |
| 答辩日期 | 2010-05-22 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 袁章福 |
| 关键词 | CO2减排 溅渣护炉 射流特性 数值模拟 氧枪喷头 |
| 其他题名 | Numerical simulations on jet behavior of the CO2 slag splashing technique in BOF |
| 学位专业 | 化学工艺 |
| 中文摘要 | 本文创新性地提出以CO2气体取代传统N2气源作为溅渣气源的转炉溅渣护炉新工艺，实现转炉炼钢车间内循环利用CO2气体的目的。根据计算流体动力学(CFD)提出了二维单孔自由射流模型和三维多孔自由射流模型，描述了天钢120吨转炉现有氧枪喷头操作CO2气源的射流特性，分析了CO2气源在转炉溅渣护炉工艺上的应用前景。 CO2气体从未在转炉氧枪中进行过顶吹操作，且氧枪顶吹气源包括O2和N2，为了分析CO2单孔自由射流特性并比较出其与N2、O2射流特性的差别，本文在CFD软件基础上建立了单个拉瓦尔喷嘴的二维自由射流数值模型。模型计算结果表明同N2、O2自由射流特性相比，CO2自由射流也遵循自模性，CO2射流的核心区长度为1.14m，而N2和O2射流核心区长度为1.33m，得出CO2射流核心区长度短；在射流冲击熔池液面的正常位置附近(1~1.5m)，CO2射流轴向马赫数也比前两种射流的轴向马赫数要小。因此，在实际的溅渣护炉操作过程中，要特别注意从压力和枪位的操作上进行探索。 在CFD软件基础上创建了三维多孔可压缩射流模型，研究120吨转炉四孔均布氧枪喷头的CO2射流特性，得出采用标准湍流模型得到的多孔射流计算结果比采用可实现化湍流模型得到的计算结果更精确。可以得到氧枪顶吹CO2自由射流各参数的详细流场分布图，多孔自由射流具有汇聚结构。氧枪喷孔倾角越小，此汇聚特性越强，喷孔夹角时多孔射流之间几乎达到完全聚合状态。CO2多孔自由射流湍流边界层具有核心不对称性，分为射流内部伴随流区和外部自由流区。模型还得出CO2射流动能头的分布变化图和各单股射流核心汇聚路径，并在此基础上推导建立了相关数学模型阐释了射流有效冲击半径和单股射流核心偏离直线路径的径向距离随着喷孔倾角减小和枪位降低而减小。 热态实验模拟了CO2作为溅渣气源的转炉溅渣护炉过程，分析了溅渣过程影响CO2转化率的因素。CO2质热转换的实验研究，为转炉减排并循环利用CO2提供了有效途径和理论依据。 |
| 英文摘要 | Basing on the slag splashing, this thesis innovatively proposes an inventive method which is to utilize CO2 as the gas source of the slag splashing instead of traditional N2 so as to handle the problem of CO2 emission. In order to investigate how promising the application of CO2 in the slag splashing is, a two-dimensional single free jet simulation model and a three-dimensional multiple jets simulation model are established according to the computational fluid dynamics to depict the CO2 jets flow behavior from the top lance of a 120t converter in Tianjin Iron & Steel Co., Ltd.. CO2 has not been applied in the top blowing process of lance in the converter. The popular operation gases of the top lance are O2 and N2, so the thesis proposes a two-dimensional single Laval nozzle simulation model by CFD software to analyze the CO2 single free jet characteristics and compare its difference with those of O2 and N2. The final computational results show that, comparing with the top blowing free jets of N2 and O2 from the same lance nozzle, the CO2 single free jet also follows the characteristic that its parameters, such as pressure, density and velocity, have the similar variation style with no relation to the dimension; however, the central core area of CO2 jet is shorter than the other two because the central core area of CO2 jet has a length of 1.14m while the other two are 1.33m. Therefore, in the practical operation of the slag splashing protection process, the operations of pressure and lance height are the critical parts to observe. This thesis continues to establish a three-dimensional compressible simulation model to discover the CO2 multiple jets properties on the basics of CFD software. Moreover, the coalescence pattern of the multiple jets has been illustrated by their Mach number distribution, and each individual jet proceeds in a curve course, bending to the lance center and tending to unite. The effects of the inclination angles on the jets coalescence were also investigated, which indicates that the lower the inclination angle is, the stronger the interfering extent between the multiple jets is. With the jets tending to attract each other and involving the ambient gas, dissimilar to the bilateral symmetry characteristic of the single jet, there is an interfering area between the multiple jets called inner companied flow part, while the other side is named the outer free flow part. With the help of this model, the dynamic power of the multiple jets to support the cavity formation was demonstrated, and additionally, a mathematical model, , concerning the effective penetration radius and digressing path of the multiple jets was proposed by taking the inclination angle and the axial distance from the nozzle tips as arguments. The future application possibility of CO2 in the slag splashing is investigated in this thesis, especially the CO2 jets behavior shows a promising application in the top blowing process, which is able to offer an effective way for the LD to reduce and reuse the CO2. An experiment was performed to simulate CO2 slag splashing, analyzing the conversion of CO2. All of these aim to provide theoretical reference for the future industrial application of CO2 slag splashing. |
| 语种 | 中文 |
| 公开日期 | 2013-09-22 |
| 页码 | 87 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1623]  |
| 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 | 王文静. CO2溅渣护炉过程射流特性的模拟研究[D]. 中国科学院研究生院. 2010. |
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