Shock wave and flame propagation characteristics during spontaneous ignition of high-pressure (up to 35 MPa) hydrogen released into the atmosphere through a tube

Higher compression ratios (exceeding 350) characterize modern hydrogen storage systems, where high-pressure releases may induce spontaneous ignition. Extending beyond conventional sub-10 MPa studies, this work systematically investigates shock wave and flame dynamics during 10–35 MPa hydrogen releases through a tube, with particular focus on how release pressure and burst disk rupture characteristics affect ignition mechanisms. It has been demonstrated that, at design pressures over 25 MPa, the enhanced thickness of the burst disk induces a markedly nonlinear rupture process. This, in turn, engenders complex interactions between the generated shock waves and turbulent mixing. Following spontaneous ignition, two flame front detachment modes emerge: (1) a Y-shaped bifurcation formed by counter-rotating vortex pairs, and (2) axisymmetric single-vortex ring shedding. These results provide critical insights for the safety design of hydrogen infrastructure and demonstrate that regulating the burst disk opening ratio of the burst disk can effectively mitigate spontaneous ignition risks.