Bidirectional propagation characteristics of gas explosion disturbed by accumulated obstacles with varied blockage ratios

• Published in: Fuel (Guildford) 2024-10, Vol.374, p.132472, Article 132472
• Main Authors: Lu, Yansen, Zhong, Xiaoxing, Liu, Zhenqi, Zhong, Qiu, Chen, Tengfei
• Format: Article
• Language: English
• Subjects: Accumulated obstacles; Bidirectional propagation; Blockage ratio; Gas explosion
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.132472

•Variations in the flame morphology, speed, and peak explosion overpressure in opposite flame directions are analyzed in this article.•The relationship between peak explosion overpressures in the left and right directions depended on the blockage ratio in each direction.•Accumulated obstacles can significantly increase the flame propagation speed and the peak overpressure in gas explosions. Coal mine gas explosions often occur in confined areas with accumulated obstacles. To investigate the effect of the blockage ratio (BR) of accumulated obstacles on the bidirectional propagation characteristics of gas explosions, this study conducted experiments using different BRs of accumulated obstacles in opposite flame propagation directions in a channel. Variations in the flame morphology, speed, and peak explosion overpressure in both directions were analyzed. Results indicate when the BR in either direction reaching 60% or above, a reverse propagation flame formed in the direction with a larger BR. With one direction completely blocked (BR = 100%) and the BR in the other direction lower than 60%, a Helmholtz cloud-like flame formed in the completely blocked direction. Effect of the accumulated obstacles on the flame speed in either direction shifted from suppression to acceleration as the BR in the other direction increased. When the BR in either direction was 80%, the effect of the accumulated obstacles on the flame speed in the same direction changed from suppression to acceleration as the BR in the opposite direction increased. The relationship between peak explosion overpressures in both directions depends on the BR in each direction. When the BRs in both directions did not exceed 60%, the higher peak overpressure appeared in the direction with a large BR. However, once the BR in either direction exceeded 60%, the peak overpressure was lower in the direction with a larger BR.