建筑群外埋地燃气管道泄漏的风险性评估

Leakage risk evaluation of buried gas pipeline outside the buildings

针对建筑群外埋地燃气管道穿孔泄漏问题,利用Gambit2.4建立三维仿真模型,并运用CFD软件Fluent14.0分别对不同环境温度、湿度条件下,燃气在土壤和大气中的连续泄漏扩散工况进行了数值模拟。对比分析了环境温度、相对湿度耦合作用下对燃气扩散的影响及浓度分布规律。研究结果表明,从泄漏口喷出的燃气首先在土壤层中迅速扩散,致使上方地表附近的浓度值很快达到了爆炸下限和上限。透过地表的燃气遇到两侧建筑物时,在迎风侧和背风侧方向分别形成不同的浓度扩散区域。受不同湿度和温度的影响,部分建筑物表面的预警浓度所处高度发生了明显的变化。案例研究结果可评估燃气泄漏事故的范围大小和指导人员及时有效地疏散。

In view of the problem of buried gas pipeline piercing leakage outside the buildings ,a three‐dimensional simulation model was established with Gambit2 .4 .The continuous leak diffusion circumstance of gas in soil and atmosphere were carried out through numerical modeling by CFD soft‐ware Fluent 14 .0 under different ambient temperature and humidity .The influence factor of gas dif‐fusion and the distribution regularity of concentration were comparatively analyzed under the coupling effect of ambient temperature and relative humidity .The research result showed that the gas ejecting from the leakage mouth first spread rapidly in the soil layer ,resulting in the concentration of the up‐per surface quickly reaching the lower explosive limit and upper explosive limit .As the gas permea‐ting through the earth surface ,it influenced both sides of the building .Different concentration diffu‐sion regions also formed on the windward side and the leeward side direction .Affected by different humidity and temperature ,for some buildings ,the warning concentration on the height of surface changed obviously .T he case study results could assess the scope of the gas leak accident and effective‐ly evacuate the masses in time .