城市综合管廊燃气爆炸传播特性实验研究

Experimental study of the propagation characteristics of gas explosions in urban utility tunnels

随着中国城镇化建设的快速发展,容纳天然气、供热、给水、电力等多种市政管线于一体的综合管廊已成为保障城市“生命线”运行的重要基础设施。天然气管线作为其中最具威胁的危险源,一旦发生泄漏极易在管廊受限空间内形成易燃易爆气体云,给综合管廊安全运行带来巨大的爆炸风险。为揭示多因素影响下综合管廊复杂受限空间内燃气爆炸传播特性,有效支撑管廊燃气爆炸事故后果评估及安全防护需求,该文使用自主研制的综合管廊燃气爆炸实验系统研究了甲烷体积分数、泄压口和舱内附属设施(燃气管道、配电箱、灭火箱等)对火焰传播过程和超压分布的影响。结果表明:甲烷体积分数为9.5%时爆炸超压达到峰值;与封闭管廊模型相比,综合管廊预设的通风口可以起到较强的泄压作用,超压峰值衰减率达28.4%;燃气舱内附属设施会加速火焰传播过程并导致更大的超压峰值。该研究能为提升综合管廊天然气舱的防灾减灾能力提供理论和技术支撑。

The rapid urbanization in China has led to many utility tunnels containing a variety of municipal pipelines including natural gas, heating, water and electrical power that are key infrastructure components in cities. The most dangerous hazard is the natural gas pipelines that can leak to form explosive gas clouds in the confined tunnels which brings huge explosion risks to the safe operation of the utility tunnels. The propagation characteristics of gas explosions in a complex, confined utility tunnel were studied experimentally as a function of various factors to support safety control and assessments of gas explosions in utility tunnels. The experiments studied the effects of methane concentration, pressure relief ports and auxiliary facilities such as the gas pipeline design, distribution boxes and fire boxes on the flame propagation and the overpressures. The results show that the maximum overpressure occurs for a methane concentration of 9.5%, vents in the tunnel significantly reduce the overpressures compared with closed utility tunnels, and the peak overpressure attenuation rate is 28.4%. Auxiliary facilities in the tunnel accelerate the flame propagation and lead to greater overpressures. This study provides guidance for improving disaster mitigation for natural gas utility tunnels in cities.