Fracture Evolution and Control of Supercritical/Dense CO2 Pipelines under Thermal-Fluid-Chemical-Mechanical (TFCM) Coupling: A Review of Initiation, Propagation, and Arrest Mechanisms

In the context of the large-scale application of global carbon capture, utilization and storage (CCUS) technology, the safety guarantee of supercritical/dense CO2 pipeline is crucial. Due to the complex phase transition, Joule-Thomson effect, chemical corrosion and material microscopic damage involved in the failure process of CO2 pipeline, the failure mechanism of CO2 pipeline is studied, the fracture process exhibits pronounced TFCM multi-field coupling characteristics, which brings challenges to the integrity assessment. In this paper, the research progress in the whole evolution process of fracture initiation, propagation and arrest in CO2 pipelines is systematically reviewed. Firstly, the induction mechanism of physical defects, stress concentration and chemical damage in the initiation stage is analyzed. Subsequently, the characteristics of phase transition decompression wave and the influence of ductile-brittle transition induced by low temperature to the resistance of fracture were discussed, and the logical relationship between macroscopic decompression behavior and local crack tip mechanical response was elucidated. In the aspect of prediction and safety assessment, the models of pipe fracture initiation failure, fracture assessment and crack arrest control are classified and reviewed, the applicability of advanced methods such as fluid-structure interaction numerical simulation and physics information neural network is discussed. Finally, the multi-scale experimental verification system covering micromechanical testing and full-scale industrial blasting is summarized, and the limitations of the current standard system and the lack of research on multi-field coupling are pointed out, the potential of digital twin and intelligent early warning system in ensuring the intrinsic safety of pipeline network is prospected.