Experimental investigation of hydrogen leakage dispersion characteristics in a scaled hydrogen refueling area

Unexpected leakage experiments were conducted using a 1:20 scale hydrogen refueling area model incorporating the actual equipment layout. The effects of leakage duration, direction, and flow rate on concentration distribution were investigated. Three concentration stages were identified: rapid growth, stable development, and decay. Leakage duration had limited effect on peak concentrations but prolonged high concentration persistence. Vertical upward leakage produced ceiling accumulation after jet impingement, with normalized concentration decaying exponentially with dimensionless distance. Horizontal leakage promoted downstream dispersion and accumulation around obstacle. Hazardous concentration distributions were inferred from monitoring points exceeding 4 VOL%. For vertical upward leakage, the high concentration region showed an approximate radial extent of 20-30 cm at model scale, corresponding to about 4-6 m at full scale. Sensors near the leakage source responded rapidly to horizontal leakage, while ceiling sensors provided better coverage for vertical leakage. These findings support hydrogen leakage risk control in the refueling area.