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根据重庆城市下水道内混合气体的流动性特点,基于层流有限速率燃烧模型建立了管道内可燃气体爆炸二维模型。通过计算机模拟与试验验证,考察了模型的可行性,系统地研究了气体组分、气体流动速度等对城市下水道内可燃气体爆炸过程的影响。结果表明,管道结构对爆炸波有显著的限制效应。在流动体系中,甲烷爆炸波位置会随气体流动向前移动,爆炸波形状也会显著变化,从而影响爆炸阈值。如气体流速为0.5 m/s时,甲烷的爆炸极限为6%～14%。气体流动速度越大,甲烷安全阈值范围越宽,当流动速度足够大时,爆炸可以被有效抑制,如气体流速大于0.85 m/s时。
According to the fluidity characteristics of mixed gas in urban sewers in Chongqing, a two-dimensional model of combustible gas explosion in pipeline was established based on laminar finite-rate combustion model. Through computer simulation and experimental verification, the feasibility of the model was investigated. The effects of gas composition and gas flow velocity on the explosion process of combustible gas in urban sewers were systematically studied. The results show that the pipe structure has a significant limiting effect on the explosion wave. In a fluid system, the position of the methane blast wave moves forward along with the gas flow, and the shape of the blast wave also changes significantly, affecting the explosion threshold. At a gas velocity of 0.5 m / s, the explosive limit of methane is 6% to 14%. The larger the gas flow rate, the wider the methane safety threshold. When the flow rate is large enough, the explosion can be effectively suppressed. For example, when the gas flow rate is greater than 0.85 m / s.