Numerical investigation on pinhole leakage and diffusion characteristics of medium-pressure buried hydrogen pipeline

Pipeline transportation of hydrogen is by far the most efficient and mature way, but special attention needs to be paid to the diffusion of hydrogen after a pipeline leakage due to the flammable and explosive nature of hydrogen. In this work, numerical simulation of pinhole leakage of the medium-pressure (0.1 up to 0.4 MPa) buried hydrogen pipeline under different conditions was carried out to analyze the effects of pressure, soil properties, pinhole location and pinhole diameter on the diffusion of leakage. The mass flow rate of the leak and the time when the ground surface is first in danger were obtained. Finally, a correlation between hazard radius of ground surface and time was established by multivariate fitting of the quantifiable influencing factors. This correlation aims to provide data support for understanding medium-pressure hydrogen diffusion characteristics and guide evacuation of ground personnel during the actual leakage.