Numerical simulation of liquid CO2 accidental release at atmospheric environment

Abstract

Investigation of the transient behaviour of high-pressure CO2 sudden release is important for the pipeline transportation safety of carbon capture and storage technology. A CFD model based on the volume of fluid method and non-equilibrium phase transition is established to simulate the high-pressure liquid CO2 release at atmospheric environment, which considers the flow domain out of the opening. The pressure drop and decompression wave speed predicted by CFD are in good agreement with the “shock tube” test results, which verifies the established CFD model. On this basis, we further investigate the transient behaviour of liquid CO2 release. The results show that the liquid-gas two-phase flow continues expanding outward from the rupture opening and sucking up the surrounding air, forming a complex three-phase under-expanded jet. It is found that the distance from rupture opening to Mach disk increases with the increase of initial pressure. It is also found that the liquid-gas CO2 mixture spurted from the rupture opening is mainly composed of liquid CO2 and a small amount of gaseous CO2 by analyzing the mass flow composition. Moreover, The static pressure and the total mass flow at the rupture opening both increase with the increase of the initial pressure, while the mass flow of the gas CO2 decreases with the increase of the initial pressure.