W型火焰锅炉水冷壁大面积变形的仿真分析及治理

发布时间：2018-06-22 01:27

本文选题：W型火焰锅炉 + 水冷壁管变形　；参考：《华东理工大学》2017年硕士论文

【摘要】：本文针对某热电公司600MW "W"型火焰锅炉前墙水冷壁多处出现大面积变形的情况,运用有限元仿真方法进行了热分析、稳定性分析和燃烧分析,根据分析结果总结出导致水冷壁变形的因素并提出合理化建议,对于锅炉的安全稳定运行具有实际指导意义。首先在ANSYS软件中使用APDL编程方法建立水冷壁的二维有限元数值模型,分析水冷壁在无垢、外壁结垢和内壁结垢三种工况下的温度场分布规律,比较三种工况下温度分布的不同之处,结果表明内壁结垢会使管壁温度显著升高。进一步建立水冷壁三维模型,合理简化模型和边界条件,分析其在三种工况下的温度、变形和应力分布特点。其温度场分析结果与二维模型下相吻合,内壁结垢是引起水冷壁管过热的主要因素。变形分析结果表明内壁结垢会最大程度地阻碍水冷壁管屏向下释放热变形,同时垂直于管屏方向的变形量也显著增大。应力分析结果表明,内壁结垢会造成垢层区域应力显著增大,并引起垢层上方区域的应力增大。在热应力分析的基础上,本文又对三种工况下的管屏进行了特征值屈曲分析,与无垢工况下相比,外壁结垢工况下的稳定性系数和模态无明显变化。内壁结垢时,稳定系数显著减小,并且失稳模态也有不同之处。结合之前的热分析结果说明内壁结垢引起水冷壁的变形可能性最大,需要对水冷壁除垢。最后利用Fluent软件对锅炉进行燃烧模拟。通过分析炉内温度场、速度场以及过量空气系数分布,发现燃烧中心偏高,配风比需调整,针对发现的不足提出增大乏气进气速度等合理性建议。本文分析方法及结论为解决电厂锅炉同类问题提供了参考。
[Abstract]:In this paper, thermal analysis, stability analysis and combustion analysis of the front wall of 600MW "W" flame boiler with finite element simulation method are carried out in view of the large area deformation of the front wall of a 600MW "W" flame boiler. According to the analysis results, the factors leading to the deformation of the water wall are summarized and some reasonable suggestions are put forward, which is of practical significance for the safe and stable operation of the boiler. Firstly, the two-dimensional finite element numerical model of water wall is established by using APDL programming method in ANSYS software, and the distribution of temperature field of water wall under three working conditions of no scale, outside wall scaling and inner wall scaling is analyzed. The difference of temperature distribution in three conditions is compared. The results show that the inner wall scaling can make the tube wall temperature increase significantly. Furthermore, the three-dimensional model of water wall is established, the model and boundary conditions are reasonably simplified, and the characteristics of temperature, deformation and stress distribution under three working conditions are analyzed. The results of temperature field analysis are in good agreement with the two-dimensional model, and the scaling of the inner wall is the main factor that causes the water wall tube to overheat. The results of deformation analysis show that the scaling of the inner wall will hinder the downward release of thermal deformation to the maximum extent, and the amount of deformation perpendicular to the tube panel will increase significantly. The results of stress analysis show that scaling on the inner wall will cause the stress of the scale layer to increase significantly and the stress of the area above the scale layer will increase. On the basis of thermal stress analysis, the eigenvalue buckling analysis of the tube screen under three conditions is carried out. The stability coefficient and mode of the outer wall under the scaling condition are not obviously changed compared with those under the non-scale condition. When the inner wall is fouled, the stability coefficient decreases significantly, and the instability modes are different. Combined with the results of thermal analysis before, it is shown that the possibility of water wall deformation caused by scaling on the inner wall is the greatest, and the scale removal of the water wall is needed. Finally, the boiler combustion simulation is carried out by fluent software. By analyzing the temperature field, velocity field and excess air coefficient distribution in the furnace, it is found that the combustion center is on the high side and the air distribution ratio needs to be adjusted. The methods and conclusions of this paper provide a reference for solving the similar problems of power plant boilers.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE963

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