Numerical Simulations of Suppression Effect of Water Mist on Hydrogen Deflagration in Confined Spaces

Hydrogen safety issues attract focuses increasingly as more and more hydrogen powered vehicles are going to be operated in traffic infrastructures of different kinds like tunnels. Due to the confinement feature of traffic tunnels, hydrogen deflagration may pose a risk when a hydrogen leak event occurs in a tunnel, e.g., failure of the hydrogen storage system caused by a car accident in a tunnel. A water injection system can be designed in tunnels as a mitigation measure to suppress the pressure and thermal loads of hydrogen combustion in accident scenarios. The COM3D is a fully verified three-dimensional finite-difference turbulent flow combustion code, which models gas mixing, hydrogen combustion and detonation in nuclear containment with mitigation device, or other confined facilities like vacuum vessel of fusion and semi-confined hydrogen facilities in industry, such as traffic tunnels, hydrogen refueling station etc. Therefore, by supporting of the European HyTunnel-CS project, the COM3D is applied to simulate numerically the hydrogen deflagration accident in a tunnel model, being suppressed by water mist injection. The suppression effect of water mist and the suppression mechanism is elaborated and discussed in the study.