Temperaturt And Thermal Stress Analysis Of The Steam Pipe And Correlative Branch Pipe Of Power Plant

The steam pipe and correlative branch pipe of power plant are detected to appear thermal diffuse crack, which influence the normal run of the generator severely. To study the reason of appearance of the thermal diffuse crack, Temperature and thermal stress analysis of the steam pipe and correlative branch pipe was performed with finite element analysis method.The distribution of Temperature and thermal stress field were confirmed and a proposal was tabled which applied for prevent the appearance of thermal diffuse crack.A test platform was designed and built according to the structure parameters of steam pipe in power plant. Flow controller, temperature controller and pressure regulator were used for regulating the operating mode. Onsite pipes'temperature was measured by thermocouples and plotted into variation graphs. From analysis of these graphs some preliminary conclusions and basis were determined for computation in the next steps.Study the heat transfer theory and water&steam's portfolio formula, and then a computational method of boundary condition parameters which is suitable for engineering application was determined. This algorithm, which is powerful in engineering calculation, was realized. The result of programming calculation and experience formula calculation was compared, verified the accuracy of the programming calculation, and confirmed the boundary condition parameters which will be used in Finite Element Analysis.Temperature field of the steam pipe and correlative branch pipe were analyzed in test and the result was compared with test data, the reliability of calculation was verified. The finite element model of the steam pipe in power plant was built, and the solution with the data measured in power plant was verified in ANSYS. The No.120, 180, 240, 300, 360, 420, 480 minutes'pipes'temperature field, thermal gradient field and thermal tress field were calculated. The reason of thermal cracks, the stress concentration region and the time and location of the maximum tress were determined which is useful for life prediction.The average life expectancy formula of 12Cr1MoV was gained by derivation calculating which based on rupture strength formula of metal material. The forecast result...