温度交变下液态乙烷回气管线热应力数值计算与现场测试*

为解决低温交变载荷下液态乙烷回气管线面临的安全问题，采用有限元法和现场试验研究管线在低温交变载荷下无裂纹和含轴向裂纹管线的热应力分布。结果表明:管内温度沿周向和轴向分布具有较大的不均匀性，内外壁温度分布趋势基本相似；随着计算时间的延长，管线整体热应力先增大再减小；卸压、温度回升过程中，管内温差逐渐减小，热应力逐渐减小；裂纹处的热应力大于远离裂纹及无裂纹处的热应力；对管线热应力变化进行现场监测，试验数据与仿真结果吻合。研究结果可为低温情况下液态乙烷回气管线的方案设计提供参考和指导。

Numerical calculation and field test of thermal stress of liquid ethane return gas pipeline under alternating temperature

In order to solve the safety problem of liquid ethane return gas pipeline under the low temperature alternating load,the thermal stress distribution of the pipeline without crack and the pipeline with axial crack under the low temperature alternating load was studied by using the finite element method (FEM) and field tests.The results showed that the circumferential and axial temperature distribution in the pipe had the great inhomogeneity.The temperature distribution trend of the inner and outer wall of the pipeline was basically similar.With the extension of calculation time,the overall thermal stress of the pipeline increased first and then decreased.In the processes of pressure relief and temperature upturn,the temperature difference in the pipeline and the thermal stress decreased gradually.The thermal stress at the crack was much larger than those at the location far away from the crack and the location without crack.The thermal stress change of the pipeline was monitored on site,and the test data was consistent with the simulation results.The results can provide reference and guidance for the scheme design of liquid ethane return gas pipeline at low temperature.