Effect of obstacle opening position on H2/O2 detonation reinitiation and quenching in an obstructed channel

In the field of explosion dynamics, clarifying the impact of obstacles with opening structure on detonation behavior is crucial for industrial explosion prevention. This study employs the OpenFOAM-based DCRFoam solver to numerically investigate the effect of obstacle opening position on detonation propagation, and uses H 2 /O 2 mixtures to sustain stable detonation. A dimensionless parameter, defined as the ratio of the distance from the opening to the bottom wall to that from the opening to the top wall, is used to characterize the opening's position and the asymmetry of the obstacle's structure. This parameter is incrementally adjusted from 0 (unilateral opening) to 1 (central opening). Through this approach, the effects of opening position on detonation quenching and re-initiation behavior are thoroughly analyzed. This study demonstrates that detonation propagation is jointly influenced by the obstacle blockage ratio and opening position. Specifically, when the obstacle blockage ratio is relatively low, multiple detonation cells can be accommodated within the opening, and varying vertical opening positions result in distinct formation processes of transverse detonation waves. Offsetting the opening position from the axis can increase detonation reinitiation distance by at least 37.2 % and moderately weaken the detonation intensity after reinitiation. When the obstacle blockage ratio is relatively high, the opening position exerts a pronounced effect on the quenching characteristics of diffracted detonation, particularly when the opening position is offset from the axis beyond a critical threshold (but remains non-adjacent to the wall). During the diffraction process, initial collisions of the detonation wave with the wall augment shock intensity, effectively suppressing the detonation quenching. • H 2 /O 2 detonation propagation under the effects of both obstacle blockage ratio and opening position is studied. • Opening position affects transverse detonation wave formation mechanism under low blockage ratio conditions. • Offset-axis opening weakens Mach reflection intensity. • Offset-axis opening increases reinitiation distance and weakens the intensity of detonation after reinitiation. • Offset-axis opening suppresses detonation quenching under high blockage ratio conditions.