Fracture behaviors of supercritical CO2 pipelines and natural gas pipelines
The core of pipeline crack arrest control lies in the prediction of crack arrest toughness.The classic crack arrest prediction method established for early natural gas pipelines is no longer applicable for supercritical CO2 pipelines.To reveal the reasons for this situation,it is necessary to clarify the difference in fracture behaviors between supercritical CO2 pipelines and natural gas pipelines.To solve this problem,the existing simulation method for dynamic crack propagation in natural gas pipeline was modified to make it suitable for supercritical CO2 pipeline.Then,the reliability of the modified numerical simu-lation method was verified by the full-scale burst test.Using the validated simulation method,a systematic comparison was made among the pressure distribution,the crack propagation length,the crack velocity,and the other fracture behavior laws during crack propagation of supercritical CO2 pipelines and natural gas pipelines.The results show that the difference in pres-sure distribution behind the crack tip for the two pipelines is the main reason why the crack arrest control method of natural gas pipeline is no longer applicable to the supercritical CO2 pipeline.Compared with the natural gas pipeline,the crack of supercritical CO2 pipeline is more difficult to arrest and has more serious consequences.This work reveals the difference in fracture behaviors between supercritical CO2 pipelines and natural gas pipelines.
CO2 pipelinecrack arrest controldecompression modelGurson-Tvergaard-Needleman(GTN)modelfrac-ture behavior
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