CO_(2)管道裂纹韧性扩展速度数值模拟

Numerical simulation of ductile crack propagation velocity in CO_(2)pipeline

【目的】碳捕集、利用与封存技术是减少CO_(2)排放的重要战略储备技术,超临界CO_(2)管道运输是连接碳捕集与碳封存最经济有效的方式。受超临界CO_(2)的减压波特性与CO_(2)的焦耳-汤姆逊效应影响,管道断裂后容易发生长程裂纹扩展,使得管道运行安全受到威胁。【方法】为探究超临界CO_(2)管道的裂纹扩展机理,选取L360M管道的母材横向试样开展了示波冲击试验,建立数值仿真模型并应用内聚力模型描述材料损伤,通过对比试验曲线与模拟曲线,对内聚力模型参数进行标定;建立超临界CO_(2)管道裂纹扩展有限元模型,将校准的内聚力模型参数输入有限元模型中开展管道裂纹扩展模拟,探讨内压、壁厚、管径等因素对管道裂纹扩展速度的影响。【结果】内聚力模型可以较好地模拟裂纹动态扩展过程,所得模拟结果与试验结果总体趋势一致,经过试验校准及验证的内聚力模型参数可用于管道模型裂纹扩展的数值模拟;对于超临界CO_(2)管道而言,增大内压与管径、减小壁厚都会增加管道裂纹扩展速度。【结论】计算得到了超临界CO_(2)管道在不同管径及壁厚下对应的止裂压力与适用于直径323 mm管道的最小壁厚,研究结果可为超临界CO_(2)管道裂纹止裂提供理论基础,具有一定实际工程参考意义。(图17,参27)

[Objective]Carbon Capture,Utilization,and Storage(CCUS)technology is recognized as a crucial technology for strategically reducing CO_(2)emissions.Supercritical CO_(2)pipeline transmission represents the most cost-effective method to connect carbon capture with carbon storage.Due to the decompression wave characteristics of supercritical CO_(2)and the Joule-Thomson effect of CO_(2),CO_(2)pipelines are susceptible to long-distance crack propagation following fractures,posing a threat to the safety of pipeline operation.[Methods]Instrumented impact experiments were conducted,using transverse specimens from the base metal of L360M pipes,to investigate the crack propagation mechanism of supercritical CO_(2)pipelines.Following that,a numerical simulation model was established and the Cohesive Zone Model(CZM)was utilized to describe material damage.By comparing curves from the experiments and simulations,parameters were calibrated for the CZM,leading to the development of a finite element model for crack propagation in supercritical CO_(2)pipelines.Simulations were performed after inputting the calibrated CZM parameters into the finite element model,to explore the effects of internal pressure,wall thickness,and pipe diameter on the crack propagation velocity.[Results]The CZM effectively simulated the dynamic progression of crack propagation,and the simulation results exhibited an overall trend consistent with the experimental results.The CZM parameters calibrated and verified through comparison with experimental results proved effective in numerically simulating crack propagation within the pipeline model.In supercritical CO_(2)pipelines,the crack propagation velocity increased with higher internal pressure,larger pipe diameter,and lower wall thickness.[Conclusion]Crack arrest pressures corresponding to different pipe diameters and wall thicknesses and the minimum wall thickness suitable for a pipe diameter of 323 mm were identified for supercritical CO_(2)pipelines through calculations based on the above results.The research outcomes lay a theoretical groundwork for understanding crack arrest in supercritical CO_(2)pipelines and offer practical engineering applications with a useful reference point.(17 Figures,27 References)