Experimental study on leakage pressure response and low-temperature law of supercritical/dense phase CO2 pipeline
In order to understand the pressure response and temperature change law of supercritical/dense phase CO2 during pipeline leakage,based on the self-designed experimental device for high-pressure CO2 pipeline leakage,the interaction mech-anism of pressure response,temperature drop characteristics and phase transition was explored,as well as the low-temperature distribution law.The results show that the pressure drop curve of pure CO2 under 19 mm diameter has two obvious stages,and there is an obvious pressure platform in the leakage of dense phase,while N2 will obviously increase the leakage rate.The tem-perature on the same section presents the distribution characteristics of"upper hot and lower cold",and the temperature drop at the release end in the pipeline axis direction is the most serious.From the perspective of phase transition,there is no obvi-ous two-phase zone in supercritical CO2 leakage,and for the dense phase,the CO2 at the bottom of pipeline will undergo the phase transition process of dense phase,liquid phase,superheated liquid phase,gas-liquid two-phase and pure gas phase.The research results can provide reference for the safe operation of pipeline discharge and the avoidance of fracture risk.