Shock waves, overpressure, and spontaneous ignition of pressurized hydrogen in T-shaped tubes

Abstract

The accidental release of high-pressure hydrogen into a tube can induce self-ignition, and special tube configurations can complicate their characteristics. Hence, this paper studies the shock waves and self-ignition in tubes with T-shaped structure. Results show that the shock wave intensity decreases after passing through the T-shaped region, and its intensity is lower in the branch pipeline. The flow field is extremely complex after shock waves enter the T-shaped region, accompanied by different shockwave structures (e.g. barrel shock and Mach disk), multiple reflections, and shock-shock interaction. In addition, the location of the bifurcation point affects not only the downstream velocity evolution but also the time of upstream pressure to reach the peak pressure. When the bifurcation point is the closest to the rupture disc, spontaneous ignition is least likely to take place. The flame intensity decreases after passing via a T-shaped zone. Besides, if the T-shaped zone is far from rupture disc, even extinguishment can occur.