【作者】 鹿高明；

【导师】 陆慧林；

【作者基本信息】 哈尔滨工业大学 ， 热能与动力工程， 2007， 硕士

【摘要】 高参数、大容量参与调峰的机组启停和变负荷过程中,较快的升压和降压以及蒸汽温度变化均会使锅炉汽包材料所承受较大的机械应力和热应力化,而频繁交变的机械应力和热应力将使金属材料产生的疲劳损伤增大,缩短锅炉汽包的使用寿命。因此开展对锅炉汽包的相关研究工作,包括锅炉汽包的瞬态温度场和瞬态应力场分布,以及在此基础上进行汽包的低周疲劳寿命计算等,对提高机组运行的安全性和可靠性具有重要的指导意义。本课题以某发电厂300MW单元机组的HG1025/18.2/540/540-PM2型亚临界自然循环锅炉的汽包为仿真研究对象,在获得试验数据的基础上,对该汽包的瞬态温度场、瞬态应力场、强度计算和低周疲劳寿命等方面开展了多学科的交叉研究。文章主要从以下几个方面进行了探讨。首先,本文建立了该汽包结构不连续区域的有限元模型,然后利用采集的数据作为计算的边界条件,采用三维有限元理论,运用国际通用大型有限元分析软件ANSYS,对机组汽包的瞬态温度场、热应力、机械应力和总应力(热和机械的耦合应力)进行了详细的计算。其次,通过对计算结果的分析,找出了汽包应力最大值的位置,并求出了危险点机械应力和总应力与蒸汽压力的比例关系。应用ANSYS程序提供的优化设计方法对汽包的局部结构进行了优化设计。作为对前面工作的总结,根据ANSYS程序的二次开发功能介绍了汽包瞬态应力分析专用程序的开发过程。论文最后引用ANSYS三维有限元瞬态分析的结果进行了锅炉汽包低周疲劳寿命计算,并与传统算法的计算结果进行了比较分析。更多还原

【Abstract】 Recent years, along with the growth of national economy, the peak-valley difference of electrical network increases day by day, a lot of thermoelectricity generator units with high running parameters and large capacity have to take part in changing the loads and even to startup-halt for adjusting the peak output. The diameter and wall thickness of the boiler drum is relative big. During the process of starting or stopping and altering loads, the pressure rising or dropping and temperature varying will make mechanical and thermal stress of the drum greatly change. The varying of the stress will result in fatigue damage to drum material and shorten the service life of the drum.For this reason, people had paid great attention to this and a lot of research work about drum was carried out. Among these work, the distribution of transient temperature field and stress field, the calculation of low-cycle fatigue life are significant to ensure boiler in good condition and safety running.The thesis takes 300MW sub-critical natural circulation boiler HG1025/ 18.2/540/540-PM2 drum of a Power Plant as object. Based on test data, the multi-disciplinary research across transient temperature field, transient stress field, Low-cycle fatigue life etc was carried out. The thesis mainly carried on the discussion in the followed respects.Firstly, author built a calculating model of the discontinuous area.Then utilized the test data as border condition of the model. The three-dimensional finite element unit was adopted; ANSYS software were used and the transient temperature field, thermal stress, mechanical stress, total stress of the drum were calculated to the model.Secondly, the position of maximum stress of the drum was found out through the analysis of calculating result, some proportionate regulation between mechanical stresses or total stresses and steam pressure also found out. Then used the optimum function of ANSYS applied to the optimization design of part structure. Finally, processed calculation of the Low-cycle fatigue life.更多还原