市政排污空间多元气体爆炸与蓄水耦合作用机理及灾害效应研究

Municipal drainage pipeline is a typical space with multiple gas and water. It is easy to form a gas explosion accident risk by the accumulation of combustible gas inside or discharged from outside. In case of gas explosion, the safe operation of the city will be affected. However, there is a lack of systematic research on the effect of water in the explosion evolution process and its coupling mechanism with the explosion shock wave and flame. This project comprehensively applies theories and methods of explosion mechanics, fluid mechanics, gas dynamics, safety science, et al, and takes gas explosion process in municipal drainage pipeline as the research object. Firstly, typical municipal drainage pipeline was selected, and field test for multiple gas was applied in order to determine the gas composition under different environmental conditions. Then, experiment was carried out by using 20L spherical explosion tank and gas explosion pipeline. Multiple gas explosion characteristics and multiple factors influence laws were analysized, and gas explosion flow field distribution laws were researched. On these basis, the microscopic process of gas explosion was reappeared by means of high-speed camera and numerical simulation methods. The collaborative effect between explosion shock wave, fire, water and solid wall was researched. The coupling disaster causing mechanism of multiple gas explosion in drainage space was revealed. Finally, gas explosion safety technology of drainage space was formed according to the solid wall's dynamic mechanical response and failure effect, which provides theoretical basis and technical support for risk assessment and safety protection of city public infrastructure facilities.

市政排污管线是一个典型的多元气体、蓄水共存空间，其内积聚或外界泄入的可燃气体极易形成气体爆炸事故风险，一旦发生爆炸将影响城市的安全运行。然而蓄水在爆炸事故演化过程中的作用及其与爆炸冲击波、火焰等耦合作用机理缺乏系统研究。本项目综合应用爆炸力学、流体力学、气体动力学、安全科学等理论和方法，以市政排污管线气体爆炸作用过程为研究对象。首先选取典型市政排污管线，对排污空间多元气体进行现场检测，确定不同环境条件下的气体组分；然后采用20L球形爆炸罐、气体爆炸管道开展实验，分析多元气体爆炸特性及多因素影响规律，研究气体爆炸流场分布规律；在此基础上借助高速摄像及数值模拟再现气体爆炸微观过程，研究爆炸冲击波、火焰、蓄水、固壁之间的协同作用，揭示排污空间多元气体爆炸耦合致灾机理；最后针对固壁动态力学响应及破坏效应，形成排污空间气体爆炸安全技术，为城市公共基础设施风险评估和安全防护提供理论依据和技术支持。

市政排污空间作为城市公共基础设施的重要组成部分，易积聚可燃气体形成爆炸性环境，一旦发生爆炸将影响城市的安全运行。本项目以市政排污管线气体爆炸作用过程为研究对象，首先以北京市典型市政排污管线为例，通过现场实测得到市政排污空间多元气体分布及影响规律。采用 20L 球形爆炸罐测试系统和数值模拟手段，开展不同配比的多元气体爆炸实验，分析多元气体爆炸特性变化规律，并改变初始温度、压力、湿度等条件，研究环境因素对气体爆炸特性的影响。模拟排污空间气体爆炸真实环境，建立不同检查井深度的污水管网模型，设置不同气体组分条件（甲烷、油气、甲烷-油气混合物等）、不同点火位置条件（检查井上部、中部和下部），研究市政排污空间气体爆炸流场分布规律。设计并加工了模拟市政排污空间气体爆炸的实验装置，采用高速摄像系统，通过观察视窗实时记录气体爆炸全过程，精确捕捉爆炸冲击波作用下蓄水流动、扬起、振荡、气化、冲击固壁等演化过程，研究蓄水对爆炸冲击波和火焰传播特性的影响及作用机理。此外，开展了不同曲率弯曲巷道、转弯结构、金属网状材料、分支管道等对受限空间爆炸灾害传播及分布的影响等研究工作，为受限空间内爆炸灾害防治和事故预防提供借鉴。