城镇地埋天然气管道泄漏诱发气云爆炸仿真

Simulation study on gas explosion induced by gas leakage of urban buried gas pipelines

为探明地埋天然气管道泄漏后爆炸流场的超压和温度特征,利用FLACS软件模拟仿真天然气管道气体泄漏扩散与爆炸事故过程,通过改变环境风速、泄漏速率、泄漏孔径3个主要影响因素来研究天然气管道泄漏爆炸事故的发展特性。结果表明:在持续稳定的泄漏情况下,可燃气体覆盖区域会趋于稳定;环境风、泄漏孔径、泄漏速率分别影响浮力扩散阶段、射流核、初始动量,从而对气体整体扩散产生影响;天然气泄漏发生爆炸时,爆炸火焰主要垂直于地面向上方传播,爆炸对建筑物产生的超压较小,但是产生的温度较高,泄漏孔径0.3 m,泄漏速率4 kg/s,无风条件下,泄漏形成的气云发生爆炸造成的超压仅为0.46 kPa,但是爆炸产生的温度高达2 135 K。

In order to explore overpressure and temperature characteristics of explosion flow field after gas leakage of buried natural gas pipelines,FLACS was used to simulate leakage and explosion accidents of pipelines. Then, development characteristics of these accidents were studied from three aspects,environmental wind speed,leak rate,and leakage aperture. The results show that under a condition of continuous and stable leakage,flammable gas’ s coverage area will be stable. Wind speed,leakage aperture and leak rate influences buoyancy dispersion stage,jet nucleus,and initial momentum respectively,thus influencing gas dispersion. When an accident happens,explosion flame mainly propagates upward,and the overpressure it generates is comparatively small,but the temperature is high. Under windless condition,when leakage aperture is 0. 3 m,leak rate at 4 kg/s,overpressure of gas cloud explosion generated by leakage is 0. 46 kPa,while high temperature generated reaches as high as 2 135. 7 K.