Numerical study on the influence of vent burst pressure on vented hydrogen explosions using a turbulent combustion model

In this study, the influence of vent burst pressure and ignition location on vented hydrogen explosions was investigated numerically using the Computational Fluid Dynamics (CFD) code GASFLOW-MPI. The numerical model accounts for two fundamental flame instabilities-thermal-diffusive instability and hydrodynamic instability-along with heat transfer mechanisms. To validate the accuracy of GASFLOW-MPI in simulating vented hydrogen explosions, the computed internal and external overpressure-time histories were compared with experimental data, demonstrating good agreement, particularly for external overpressure profiles. A detailed numerical analysis of the flow field was conducted to elucidate the mechanisms governing internal and external overpressure peaks under central and back ignition scenarios. Quantitative evaluations were performed on the expelled and consumed moles of hydrogen and oxygen, expelled nitrogen, and generated steam. Furthermore, the energy released by hydrogen combustion, as well as heat transfer via convection and radiation, was systematically quantified. Finally, the correlation between maximum internal and external overpressures and vent burst pressure was analyzed to provide deeper insights into explosion dynamics.