A study on decompression wave propagation characteristics during CO2 pipeline leakage with consideration of gas‐liquid transition

Pipelines stand as the most cost‐effective method for large‐scale transportation of CO2 from a source point to the storage site, especially over extensive distances. The potential for crack propagation following a pipeline rupture highlights the need for precise analysis of decompression wave propagation. To accurately model this, understanding the decompression wave's propagation laws becomes imperative. Although previous studies have predominantly focused on pipeline leaks within the dense phase or supercritical state, the transition from liquid to gas during leakage significantly affects the decompression wave propagation. When a gaseous CO2 pipeline ruptures, the high Joule‐–Thomson coefficient causes a swift temperature plunge, potentially leading to a gas–liquid transition. However, research on how this phase transition impacts the decompression wave characteristics is limited. To address this gap, this study proposes a transition computational fluid dynamics model to predict the decompression wave behavior. The model is validated with an industrial‐scale full‐bore rupture experiment. The results reveal that the gaseous CO2 leakage induces a pressure plateau at a certain distance from the leakage due to the gas‐liquid phase transition. The influences of initial conditions on this pressure plateau and decompression wave are also explored. This study provides valuable insights into understanding the decompression wave behaviors of gaseous CO2 pipelines, which are essential for ensuring the safety and reliability of CO2 transportation within the carbon capture and storage technology chain. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.