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

Hydrogen safety issues are attracting increasing focus as more and more hydrogen-powered vehicles are going to be operated in traffic infrastructures of different kinds such as 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 devices, or other confined facilities like vacuum vessels of fusion and semi-confined hydrogen facilities in industry, such as traffic tunnels, hydrogen refueling stations, etc. Therefore, by supporting 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 are elaborated and discussed in the study.