窨井内受限空间可燃气体爆炸特性研究

发布时间：2018-08-22 16:04

【摘要】：城市窨井内受限空间可燃气体爆炸是城市安全领域的灾害形式之一,近年来窨井内受限空间可燃气体爆炸事故的发生呈上升趋势,对城市居民造成重大的人身伤害和经济损失,甚至引发一连串的灾难性后果。因此,开展以窨井为代表的受限空间可燃气体爆炸研究,对于预防和控制此类灾害性事故发生具有重要的实际意义和科研价值。论文的创新点和主要结论有:(1)确定出窨井内气体主要成分。通过现场检测得知城市窨井内含有CH4、H2S、CO2、CO、SO2、NOX、H2、NH3等气体,其中CO、SO2、NOX、H2、NH3的含量微小,几乎为零,故城市窨井内的主要有害气体是其中所占比重较大的CH4、H2S、CO2。(2)验证了FLACS数值模拟方法的可行性。采用20L爆炸球在实验室进行可燃气体爆炸实验,同时使用FLACS软件模拟相同工况下20L球形受限空间内的可燃气体爆炸过程,对比实验与模拟结果充分验证了数值模拟方法的可行性。进而使用该数值模拟方法对窨井内受限空间气体爆炸特性进行研究。(3)获得了窨井内可燃气体爆炸规律。惰性气体CO2可以有效阻止甲烷燃烧爆炸反应正向进行,并导致反应产物浓度增大;窨井内初始压力的增大对最大爆炸压力的影响呈现出近似的线性关系;点火位置越靠近封闭端爆炸越猛烈;井盖开启状态较闭合状态爆炸压力小、火焰传播速度大;排气孔使得爆炸过程中部分可燃气体和压力释放,有类似泄压的作用;障碍物截面变化方式、趋势、布置方式对爆炸压力场和速度场均有一定影响。障碍物交错放置时的火焰传播速度和爆炸压力较平行放置时大。(4)从控制窨井内可燃气体大量产生、聚集以及完善窨井防爆管理措施两方面进行深入分析,有针对性的提出防止窨井内可燃气体爆炸的对策建议。
[Abstract]:Combustible gas explosion in the confined space of urban bass well is one of the disasters in the field of urban safety. In recent years, the occurrence of combustible gas explosion accidents in the confined space of urban bass well is on the rise, causing serious personal injury and economic losses to urban residents, and even causing a series of catastrophic consequences. The research on the explosion of combustible gas in confined space is of great practical significance and scientific research value for preventing and controlling such disastrous accidents. The innovation and main conclusions of this paper are as follows: (1) Determining the main components of the gas in the bass well. The contents of O2, NOX, H2 and NH3 are very small and almost zero, so the main harmful gases in urban bass well are CH4, H2S, CO2. (2) The feasibility of FLACS numerical simulation method is verified. The numerical simulation method was used to study the gas explosion characteristics in the confined space of the bass well. (3) The law of the gas explosion in the bass well was obtained. The inert gas CO2 can effectively prevent the methane combustion and explosion reaction. The influence of initial pressure on the maximum explosive pressure shows an approximate linear relationship; the closer the ignition position is to the closed end, the more violent the explosion is; the lower the explosive pressure is in the open state of the well cover, the higher the flame propagation speed is; and the exhaust hole makes part of the flammable gas in the explosion process. The flame propagation speed and explosion pressure are higher when the obstacles are placed interlacedly than when they are placed parallel. (4) A large number of combustible gases are produced from the control of the well, and the explosion prevention is improved. The management measures are analyzed in depth and the countermeasures and suggestions are put forward to prevent the explosion of combustible gas in the bass well.
【学位授予单位】：首都经济贸易大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X932

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