Abstract: As a crucial step in carbon capture, utilization and storage (CCUS) technology, pipeline transportation is a primary method for the large-scale transport of CO?. Due to various complex factors, supercritical CO? pipelines may face risks of leakage or rupture during operation. To address the potential gas-liquid two-phase flow during the decompression of supercritical CO? pipelines, a zero-dimensional CO? pipeline decompression model was established to investigate the multiphase flow characteristics of the internal medium during leakage. The study found that for supercritical CO? pipeline leakage, there exists a critical operating pressure; when the pipeline operating pressure exceeds this critical pressure, gas-liquid two-phase flow may occur during the leakage process.

Key words: supercritical, multiphase flow, decompression model, leakage