Numerical study of external explosion in vented hydrogen explosions

In the current study, numerical study of vented hydrogen explosions was performed utilizing computational fluid dynamics (CFD) software GASFLOW-MPI. A turbulent combustion model based on Schmidt correlation was formulated. Within this model, flame instabilities resulted from two intrinsic effects, Hydrodynamic instability, and Landau-Darrieus and Thermal-Diffusive instabilities were incorporated. The numerical simulation results revealed the mechanism of over-pressure evolution inside and outside the vessel. Notably, the mechanism of the overpressure peak induced by the external explosion was revealed. The effects of turbulence models on overpressure time profiles were investigated. Moreover, it was determined that heat transfer, arising from thermal radiation and convection, exerts only a negligible influence on the maximum internal overpressure. Subsequently, the performance of GASFLOW-MPI in simulating vented hydrogen explosions for different ignition locations (center and rear ignitions) and varying hydrogen concentrations (22 %-38 %) was assessed against experimental data. Comparative analysis revealed a close agreement between the predicted results and experimental data. Furthermore, the competency of GASFLOW in simulating medium-scale vented hydrogen explosions was validated against experimental data.