Simulation of Hydrogen-Blended Natural Gas Leakage in Confined Space

As a key enabler for carbon neutrality, hydrogen-blended natural gas utilization requires a thorough safety assessment. This study investigates leakage dispersion in a typical kitchen (4 m × 3 m × 2.8 m) using validated CFD methods. Simulations examined coupled effects of hydrogen blending ratios (0–20%), leakage types (pipe cracks/hose pinholes), and ventilation conditions. Results show hydrogen enrichment accelerates overall dispersion but intensifies methane accumulation near the source. In all scenarios, buoyancy-driven stratification formed stable combustible layers (>0.3 m thick) exceeding the mixture-specific lower flammability limit (recalculated using Le Chatelier’s law) after 25 min in confined spaces. While ventilation promoted global diffusion, it created persistent high-concentration zones (≥5% volume fraction) near leakage sources. The spatial overlap of these hazardous clouds with ignition sources significantly increases explosion risks. This research provides critical insights for developing safety standards and emergency protocols for hydrogen–natural gas mixtures.