蒸汽管道外接管座温度场与热应力场的有限元计算

应用ANSYS软件,对火力发电厂蒸汽管道以及与之相连接的接管座处的温度场和应力场进行了有限元数值模拟.采用经验公式拟合法和编程计算法计算的边界条件,可以得到类似的三维温度场和热应力场分布.在现场运行阶段,温度梯度和VonMises等效热应力最大的地方都出现在蒸汽管道与接管相接处,该处的最大热应力已经超过了材料的许用应力,很容易产生热裂纹.经验公式拟合法和编程计算法的计算结果反映了相同的启动阶段热应力变化趋势,但是编程计算法不像经验公式拟合法那样具有经验性,故工程应用性更强.

The Temperature and Thermal Stress Analysis of Steam Pipe and Correlative Branch Pipe with Finite Element Method

Temperature and thermal stress analysis of the steam pipe and correlative branch pipe in thermal power plant was performed using the finite element analysis software ANSYS.The 3D temperature field and the thermal stress distribution can be obtained by the boundary condition,which is the result of the computation through the empirical formula and computer programming.In the running time of scene,the maximum values of the thermal gradient and VonMises thermal stress occur at the conjunction of the steam pipe and its branch pipe.Because those values are beyond the scope of the material's admissible stress,cracks can easily be produced.The result of the two methods above proves the same trend of thermal stress changes.However,compared with the empirical formula,the computer programming is not so empirical and has more engineering application.