Abstract: To investigate the factors influencing the leakage and diffusion of high-pressure hydrogen in a confined volumetric space, we analyzed the effects of ambient temperature, humidity, wind speed, leakage location, and leakage rate on hydrogen concentration distribution through numerical simulation. A high-pressure hydrogen concentration variation model was developed, and sensitivity analysis based on key parameters was conducted. The results indicate that hydrogen exhibits a distinct layered diffusion characteristic within a volumetric confined space. During the transition from vertical to horizontal momentum, the vorticity distribution evolves from an initial V-shaped structure to a later two-vortex core structure. Wind speed significantly impacts the diffusion process, with hydrogen volume fraction decreasing by 22.8% at 3 m/s. Different shapes of leakage holes result in notable variations in hydrogen diffusion behavior; when the leakage area is the same, the local hydrogen volume fraction in square leak holes is 22.94% higher than in round leak holes. The leakage rate (coefficient 0.864) and wind speed (coefficient -0.988) are identified as the primary factors affecting hydrogen diffusion.

Key words: hydrogen leakage, confined volumetric space, leakage source parameters, sensitivity analysis