铁水倾倒工艺的流场特性及其伴生污染物运动规律

发布时间：2018-05-31 22:48

本文选题：高温浮射流 + 浮力羽流　；参考：《西安建筑科技大学》2015年硕士论文

【摘要】：诸多工业生产中都存在着倾倒工艺,该过程中加料罐向接收罐倾倒高温物料,高温物料在下落过程中会诱导和卷吸周围空气进入接收罐体,根据质量守恒定律,使接收罐内气体从接收罐体口溢出,从而形成高温且具有初始速度的浮射流。这部分浮射流不仅含有余热和大量有害气体还伴生粉尘颗粒。烟气和粉尘会严重影响厂房空气质量,同时给工人的健康带来巨大的危害。因此,铁水罐内铁水倾倒至转炉这一过程具有重要的研究价值。本文采用CFD方法对铁水倾倒过程进行研究,并运用基于FLUENT商业软件的两相流模型,同时加入动网格技术,最终实现铁水罐倾倒铁水过程数值仿真。首先,建立二维模型,讨论并验证浮射流和浮力羽流特性。文中提出采用两相流模型可对羽流进行数值模拟,即铁水区域与周围气体区域,模拟结果与单相流基本一致。其次,由铁水倾倒过程相界面的变化而将整个过程划分成“倒前”、“倾倒”和“倒后”三个阶段。阶段一、二分界线为铁水有无出铁水罐进入转炉。阶段三则是铁水全部进入转炉之后。第一阶段,流场较稳定,速度不大,主要处于浮力羽流阶段;第二阶段,流场复杂,速度波动较大,主要由浮力羽流和浮射流共同作用;第三阶段,由浮射流向浮力羽流过度,速度便逐渐平稳。最后,由于浮升力和动量作用气体均往铁水罐和转炉上方运动,并卷吸周围气体和粉尘,结合实际工程排风罩装问题,故在铁水罐和转炉上方取一截断面,研究整个倾倒过程断面的平均速度变化。从断面平均速度的变化趋势,可更加直观地指导工业通风。
[Abstract]:There is a dumping process in many industrial production, in which the high temperature material is dumped into the receiving tank by the feeding tank, and the high temperature material will induce and absorb the air around the receiving tank into the receiving tank during the falling process, according to the law of conservation of mass, A high temperature floating jet with initial velocity is formed by overflowing the gas from the receiving tank. This part of the floating jet not only contains residual heat and a large amount of harmful gases, but also associated with dust particles. Smoke and dust will seriously affect the air quality of factory buildings, and at the same time bring great harm to the health of workers. Therefore, the process of pouring molten iron into converter has important research value. In this paper, the CFD method is used to study the dumping process of molten iron, and the two-phase flow model based on FLUENT commercial software is used. At the same time, the dynamic grid technology is added to realize the numerical simulation of the pouring hot metal process in the molten iron tank. Firstly, a two-dimensional model is established to discuss and verify the characteristics of floating jet and buoyant plume. In this paper, a two-phase flow model is proposed to simulate the plume, that is, the hot metal region and the surrounding gas region. The simulation results are in good agreement with the single-phase flow. Secondly, the whole process can be divided into three stages by the change of the phase interface of molten iron dumping process: "before", "dumping" and "after pour". Stage one, two dividing line for molten iron with or without molten iron tank into the converter. Stage three is after all molten iron has entered the converter. In the first stage, the flow field is relatively stable and the velocity is small, which is mainly in the buoyancy plume stage; in the second stage, the flow field is complex and the velocity fluctuates greatly, mainly by the combination of buoyant plume and floating jet; in the third stage, the flow is over from floating jet to buoyant plume. The speed gradually leveled off. Finally, because the floating lift and momentum action gas move to the top of the molten iron tank and converter, and absorb the surrounding gas and dust, combined with the practical engineering exhaust air cover installation problem, so a section is taken above the molten iron tank and converter. The variation of average velocity of the whole toppling process is studied. From the change trend of average speed of section, it can direct industrial ventilation more intuitively.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X757;TF703

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