室内天然气管道微量泄漏气体扩散特性的CFD模拟  

On the CFD simulation of the methane gas leakage and dispersion from the indoor gas pipeline

作　　者：陈琪[1] 陈彩霞[1] 吴亭亭[1] 王腾[1] 方瑞[1] CHEN Qi;CHEN Cai-xia;WU Ting-ting;WANG Teng;FANG Rui(Key Laboratory of Coal Gasification and Energy,Ministry of Education,East China University of Technology,Shanghai 200237, China)

机构地区：[1]华东理工大学煤气化及能源化工教育部重点实验室

出　　处：《安全与环境学报》2018年第6期2224-2229,共6页Journal of Safety and Environment

摘　　要：以某市发生天然气管道微量连续泄漏的民用厨房为对象,实地采点测量得到泄漏源的泄漏速率为q=1.79×10^-8kg/s,以该泄漏速率为边界条件,用Fluent模拟软件研究在门窗关闭的条件下微量连续点源泄漏的甲烷气体扩散运动特性,确定室内危险区域范围。首先使用稳态模拟,得到了室内甲烷质量浓度分布,与实测数据比较,验证了模型的合理性;进一步实施非稳态模拟,发现上述微量泄漏在0.5h就可形成对人体健康有极大危害的危险接触气云。与大面积泄漏事故不同,厨房空间内管道微量泄漏事故的甲烷浓度累积较慢,形成爆炸气云的风险较小,应重点关注危险接触区域。危险接触区域面积Ad呈指数函数增长,可用Ad=e^a0+a1/t+a2估算。老旧小区集中切换天然气后,建议增加定期检漏频率,或者安装甲烷泄漏报警装置,甲烷探头安装点应选择靠近有管道连接段的墙面或下风向的墙角处。This paper is aimed at making a case study on the closed-up kitchen pipeline with its small-scale natural gas leakage.The kitchen is supposed to be built in a very old traditional residential area thick with residents.On-site measurements have been done by a methane laser detector at an average methane leakage rate of q = 1.79 × 10^-8 kg/s.The said gas leakage rate can then be used as a boundary condition for the said CFD simulation of methane gas diffusion based on a mathematical model of the above mentioned closed kitchen.Furthermore,it is supposed for the ANSYS Fluent to be adopted in the simulation model with the numerical data being post-processed to identify and determine the dangerous risk methane-filled contact area.And,in so doing,a steady state simulation of methane diffusion has been conducted with the window being open.Thus,consequently,the simulation result of the methane content concentration distribution has been verified well in accord with the actual measurement.Nevertheless,on the contrary,if an unsteady simulation test has been done in the condition with the window or windows entirely shut up with the same kitchen of the mathematical model,the results should be such that even with a minor trace methane gas leakage,there would be a dangerous contact cloud to be produced in a period of 7 hours,which would be a death-threatening harm to human health.Though different from the large scale leakage accidents,such kind of trace gas leakage in the indoor condition can be predicted free from a serious mixed explosion cloud,for such dangerous contact cloud should be focused when a trace gas leakage can only take place in the room-in or indoor case.Based on the post-processing of the simulation of the gas dispersion during 7 hours,the dangerous contact area Adis supposed to increase exponentially with time,which can be estimated by the following equation:Ad=ea0+a1/t+a2.However,if the synthesis gas can be replaced by the natural gas for the old-fashioned residential districts of a city with thick populatio

关 键 词：安全工程 管道泄漏 气体扩散 CFD模拟 危险接触区域 民用天然气 

分 类 号：X956[环境科学与工程—安全科学]