Experimental study on hydrogen-air premixed gas explosion in confined space

• Published in: Energy sources. Part A, Recovery, utilization, and environmental effects Recovery, utilization, and environmental effects, 2024-12, Vol.ahead-of-print (ahead-of-print), p.1-12
• Main Authors: Zhou, Ning, Wang, Teng, Li, Xue, Ni, Pengfei, Zhao, Huijun
• Format: Article
• Language: English
• Subjects: 90° bend pipeline; hydrogen explosion; shock response; straight pipeline
• ISSN: 1556-7036; 1556-7230
• DOI: 10.1080/15567036.2020.1782535

In order to explore the explosion characteristics of hydrogen-air premixed mixtures and to characterize the damaging effect of the explosion shock wave on the surrounding structures, a closed straight detonation pipeline is designed and applied to simulate a confined space in this study. The inner diameter of the designed pipeline is 6.4 m long and 125 mm wide. The results show that the maximum flame speed of the most combustible premixed gases usually occurs near the equivalent ratio of 1 (hydrogen volume concentration is 29.6%). However, because of the influence of Graham's law in chemical reaction kinetics, the maximum flame speed of hydrogen/air premixed gas appears near the equivalent ratio of 1.5 (hydrogen volume concentration is 39.6%). At this concentration, the maximum flame propagation speed reaches 1810 m/s and the pressure peak reaches 1.53 MPa. The elbow structure has a significant effect on the explosion flame. The explosion pressure and flame propagation velocity drop sharply when the premixed gas enters the bend. The explosion pressure is reduced by 11.3% and the flame propagation velocity is reduced by 66.59%. However, the velocity of flame propagation increases by a maximum of 34.41%, and the explosion pressure increases by a maximum of 26.1% when the premixed gas passes the turning point of the elbow. The thin-wall strain response of the pipeline is in good agreement with the explosion pressure.