水泥生产用分解炉传热和流动特性的数值模拟及实验研究

发布时间：2018-06-21 19:19

本文选题：分解炉 + 数值模拟　；参考：《山东大学》2015年硕士论文

【摘要】：新型干法水泥生产技术是目前世界上最先进的水泥生产技术,近年来,新型干法水泥生产技术日益成熟,并向着系列化、大型化、生态化方向发展。窑尾预分解系统是新型干法水泥生产过程中的核心部分,而分解炉是窑尾预分解系统的核心设备。本文采用实验测定和数值模拟相结合的方法,对山水集团山东水泥厂2000t/d 3#生产线的分解炉进行了传热和流动特性的研究。主要工作如下：1、结合现场情况,合理布置监测点和采样点,对实际工况中的相关物理量进行了实验测定,并得到所需数据。2、利用Pro/ENGINEER软件对分解炉建立几何模型,并对分解炉的几何模型进行网格划分。选取几组不同数量的网格,进行网格独立性验证,确定数值模拟的最佳网格数目。3、使用FLUENT软件,选用标准k-ε模型对分解炉气相流场进行数值模拟,得到了气相流场的速度分布云图、速度矢量图和系统流线图。结果表明,气体整体上呈螺旋上升,炉内多处存在环状涡流和明显的涡旋现象,但是炉内速度分布并不对称。4、在气相流场模拟的基础上,选择离散相模型,对分解炉气固两相流场进行数值模拟,得到了速度分布云图、生料颗粒轨迹图和煤粉颗粒轨迹图。结果表明,速度分布的整体趋势和气相流场类似,生料颗粒和煤粉颗粒在分解炉内扩散状况良好,几乎充满整个炉体空间,生料颗粒在炉内的最长停留时间达到了11.9s。5、选用借助概率密度函数(PDF)的非预混燃烧模型,对分解炉煤粉燃烧过程进行数值模拟,得到了煤粉燃烧流场的速度分布、温度分布、各组分浓度分布情况和煤粉颗粒轨迹图。结果表明,热态流场的的速度分布情况和冷态流场趋势大致相同,但整体速度要高于冷态气相流场,同样存在速度分布不对称的现象；温度场的分布存在出口温度太高、下部混合室近壁区温度过高等不合理之处；炉内O2、CO2、CO浓度分布合理。煤粉颗粒分散状况良好。6、针对数值模拟的结果,对该生产线的分解炉结构提出相应的改进方案,并对改进后的分解炉模型分别进行了气相流场、气固两相流场和煤粉燃烧的数值模拟。与改进前对比,速度场、温度场均得到一定改善。
[Abstract]:The new dry process cement production technology is the most advanced cement production technology in the world at present. In recent years, the new dry process cement production technology is becoming more and more mature, and it is developing towards serialization, large-scale and ecological direction. The kiln end precalciner is the core part of the new dry cement production process, and the calciner is the core equipment of the kiln tail precalciner system. In this paper, the heat transfer and flow characteristics of the calciner in the 2000t/d 3# production line of Shandong cement Plant of Shanshui Group are studied by means of the combination of experimental measurement and numerical simulation. The main work is as follows: 1. According to the field conditions, the monitoring points and sampling points are reasonably arranged, and the relevant physical quantities in the actual working conditions are measured experimentally, and the required data .2. the geometric model of the calciner is established by using Pro/ engineer software. The geometric model of calciner is meshed. Several different numbers of meshes were selected to verify the grid independence, and the optimum mesh number of numerical simulation was determined. The standard K- 蔚 model was used to simulate the gas phase flow field in the decomposed furnace using fluent software. The velocity distribution cloud diagram, velocity vector diagram and system streamline diagram of gas phase flow field are obtained. The results show that the gas is spiraling upward, and there are annular eddy currents and obvious vortex phenomena in many places in the furnace, but the velocity distribution in the furnace is not symmetrical .4. on the basis of gas phase flow field simulation, the discrete phase model is chosen. The gas-solid two-phase flow field in the decomposing furnace was simulated, and the velocity distribution cloud diagram, raw meal particle trajectory diagram and pulverized coal particle trajectory diagram were obtained. The results show that the overall trend of velocity distribution is similar to that of gas-phase flow field. The diffusion of raw and pulverized coal particles in the calciner is good and almost fills the whole furnace space. The longest residence time of raw meal particles in the furnace reaches 11.9s. 5. By using the non-premixed combustion model with probability density function (PDF), the combustion process of pulverized coal in calciner is simulated numerically, and the velocity distribution and temperature distribution of pulverized coal combustion field are obtained. Distribution of each component concentration and trace map of pulverized coal particles. The results show that the velocity distribution of the hot flow field is approximately the same as that of the cold flow field, but the overall velocity is higher than that of the cold gas phase flow field, and the velocity distribution is asymmetrical, and the outlet temperature of the temperature field is too high. The distribution of CO _ (2) CO _ (2) CO _ (2) in the furnace is reasonable. According to the result of numerical simulation, the improved scheme of calciner structure of this production line is put forward, and the gas phase flow field of the improved calciner model is carried out respectively. Numerical simulation of gas-solid two-phase flow field and pulverized coal combustion. Compared with the former, the velocity field and temperature field are improved to some extent.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ172.6

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