Effects of internal intervention in tubes on shock wave attenuation, formation and propagation of flame during high-pressure hydrogen release

• Published in: Process safety and environmental protection 2024-12, Vol.192, p.313-320
• Main Authors: Tang, Jing, Jiang, Guangbo, Zhang, Songlin, Zeng, Qian, Tian, Jiamin, Jin, Kaiqiang, Sun, Jinhua, Duan, Qiangling
• Format: Article
• Language: English
• Subjects: Flame characteristics; Hydrogen; Internal intervention; Shock attenuation; Spontaneous ignition
• ISSN: 0957-5820
• DOI: 10.1016/j.psep.2024.10.060

Experiments on the impacts of the combination of fin structure and expansion chamber on shock wave attenuation, hydrogen ignition, and flame characteristics during high-pressure hydrogen release were carried out. The fin is a four-edged platform hollowed out on all sides. The inflated upper and lower tube walls are located 85, 95, and 105 mm away from the nickel burst disk. With the incident shock wave traveling through the fin, the reflected shock and the superposition of multiple reflected shock waves appear, and the reflected shock wave intensity can equal that of the release pressure. The decrease of the incident shock wave intensity behind the fin leads to the decrease of the non-uniformity of the mixed layer temperature, further causing the decrease of the flame propagation velocity. The presence of fins increases the probability of ignition in the fin region and the critical release pressure for ignition is significantly lower than that in the barrier free tube, mainly because the fin inside intensifies the hydrogen/air mixture, resulting in a lower minimum ignition energy required for self-ignition. Furthermore, the decrease of flame propagation velocity leads to the increase of hydrogen consumption inside the tube and the decrease of shock overpressure outside.