Analytical studies on effects of wind on dispersion of hydrogen leaked in a partially open space

In order to elucidate ventilation and exhaust of hydrogen (H2) leaked in a partially open space (room) practically, the effects of outer wind (forced external flow) on them were studied analytically by using a CFD (computational fluid dynamics) code in the room of experimental 'Half-size Hallway model (1/2 Hallway model),' which has a H2 release hole on the bottom, one vent on the roof (Roof vent) and another vent on the side (Door vent): external air flowed in the room from the Door vent and then H2 was discharged outside from the Roof vent. The H2 concentration distribution in the room was divided into two layers at the height of Door vent, with a high concentration layer above it and a low concentration layer below it, forming a stratified interface. When the wind speed blown into the room increased, the combination of the Realizable k-epsilon turbulence model and the turbulence Schmidt number of 1.0 improved the reproducibility of the analysis results of H2 concentration distribution. The trial analysis suggested that the concern that wind would increase the indoor H2 concentration could be reduced by using the plate with a simple structure in which two plates were crossed on the Roof vent.