地下暗渠内气体爆炸影响范围的仿真研究

Simulation on influence area of gas explosion in an underground culvert

为了解不同点火位置及阻塞率对暗渠爆炸强度的影响,量化爆炸事故对建筑物及人员的影响范围,以甲烷为研究气体,在暗渠两侧共设置2个监测点,用于分析超压的变化,同时定义2个不同点火位置和4种不同障碍物分布工况,用FLACS软件模拟各工况下暗渠内瓦斯的爆炸,获取地面的超压分布状况,并分析超压的影响范围,为暗渠内管道及地上建筑物的布置提供依据。结果表明:在同一工况下,点火位置不同,地面超压的分布状态不同;爆炸强度随障碍物阻塞率增加而增大,且当障碍物阻塞率相同时,爆炸强度随障碍物密度增加而增大;根据FLACS的模拟结果,可得到超压的影响范围,并以此确定建筑物及人员的安全距离,为城市安全规划提供参考。

This paper aims to provide a reference for the layout of the pipeline in the culvert and the buildings on the ground.Specifically,to understand the impact of different ignition positions and blocking rates on the explosion intensity in the culvert,as well as quantify the impact of the explosion accident on the building and personnel,we use methane as the research gas and set up two different monitoring points for overpressure analysis.In this study,two ignition positions and four obstacle distribution conditions are considered.The FLACS software is used to simulate the gas explosion in the culvert under various working conditions,which enables us to collect the distribution of overpressure on the ground and analyze the influence range of the overpressure.The results show that:(1) under the same obstacle setting condition,the overpressure distribution on the ground varies with different ignition positions.The explosion overpressure has a greater impact on both ends as compared to the middle when the ignition source is located on one end of the culvert,while the explosion overpressure gradually decreases from the middle to the two ends when the ignition source is located on the middle of the culvert.Furthermore,under the middle ignition condition,the influence range of the overpressure in the middle is larger than that in both ends,which is more instructive for the determination of the safety distance.(2) The explosion intensity is not only related to the blocking rate but also increases with the obstacle density.Therefore,in practice,the underground pipeline in the culvert should be reasonably arranged to control the explosion risk.(3) The impact range of overpressure can be obtained according to FLACS simulation results,which enable us to determine the safety distance for buildings and personnel and provide a guide for the safety planning of cities.