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本文对国产12.5万千瓦机组锅炉汽包壁的温度场和应力场按照不同的温度变化速度、运行方式和边界条件,利用Crank-Nicolson六点隐式差分格式进行了数值计算。为了使计算结果更接近汽包壁的传热情况,又考虑了汽包保温层的不稳定导热现象,按双层壁导热的物理模型建立了定解问题,给出了用追赶法求解定解问题的计算程序和结果,并与其他简化计算结果作了比较和分析。本文最后分别按美国的“ASME锅炉和受压容器规范”和西德“蒸汽锅炉技术规程”计算了12.5万千瓦锅炉汽包的低周疲劳寿命。
In this paper, the temperature field and stress field of domestically produced 125 MW unit drum wall are calculated by Crank-Nicolson six-point implicit difference scheme according to different temperature changing speed, operation mode and boundary conditions. In order to make the calculation result closer to the heat transfer condition of steam drum wall, the unstable thermal conduction of drum insulation was also considered. The problem of fixed solution was established according to the physical model of double-wall thermal conductivity. The calculation procedure and result of the problem are compared and analyzed with other simplified calculation results. At the end of this paper, the low cycle fatigue life of a 12.5 MW boiler drum is calculated according to the ASME Boiler and Pressure Vessel Code and the West German Steam Boiler Technical Code respectively.