甲烷爆炸对建筑物内外压力场分布的影响

天然气泄漏导致的预混爆炸,会严重威胁周围人员的生命及财产安全,因此掌握气体预混爆炸在建筑物周围产生压力场的分布至关重要。基于Fluent软件,建立了适用于甲烷无约束爆炸超压的计算模型,并通过实验数据对其修正,结果表明:在化学计量浓度下参与燃烧爆炸的预混气体体积约为总体积的1/3,即当量体积。在此基础上建立了适用于甲烷约束爆炸的仿真模型,分析了建筑物高度和宽度对建筑周围压力场的影响,并进一步研究了气体爆炸对建筑物内部压力场分布的影响。结果表明,在建筑物不失效前提下,背对爆炸源一侧中上部为较安全区域,在紧急爆炸事故中,盲目的向下逃生,反而容易受到爆炸超压的强烈冲击。

Effect of methane explosion on distribution of pressure field inside and outside buildings

Premixed methane gas explosions caused by leaked natural gas pose a serious threat to the lives, which may lead to casualties and buildings collapse. So it is important to know the distribution of pressure fields around buildings when there is an explosion. Then people can escape to a relative safe place. Based on the Fluent software, a calculation model suitable for the overpressure of the unconstrained explosion of methane was established, and it was corrected by experimental data. The results show that highest accuracy appears in the SAS turbulence model and the Laminar Finite-Rate model when there is no object to limit the explosion, and that the volume of methane air mixture involved in combustion explosion at the stoichiometric concentration is about 1/3 of the total volume. Then a model for methane unconfined explosion is established. The influence of building height and width on the pressure field is analyzed. Furthermore, the distribution of pressure field inside the building is studied. And the results show that the middle-upper part of buildings is safer than the bottom when the building does not fail. The width of a building affects its resistance to positive overpressure. But neither the height nor the width of the building will affect the change of negative overpressure. Thus in the emergency explosion accidents, it will more vulnerable to the strong impact of positive and negative overpressure that escaping to the bottom blindly.