Abstract: City gas pipelines are always under the threat of municipal construction.Unlike in the wild,the building of the city will cause lots of trouble to the dispersion of the gas released,and the lives and property safety of people may be threatened. The dispersion of the city gas released in the street canyons was analyzed based on the two-dimensional CFD model.The situation before and after the shutting down of the block valves were studied respectively.The numerical simulation results show that the wind plays a leading role on the dispersion,and the aspect of the street canyon has significant effects on inner vortex airflow fields which will make the gas difficult to disperse.

Key words: Citygas , Release and dispersion , Numerical simulation , Street canyon , Vortex airflow field

摘要： 城市燃气管道的安全时常受到市政建设的威胁而破坏,与天然气管线野外泄漏的情况不同的是,市区复杂的建筑环境会对气体的扩散情况造成干扰,严重危害人员财产安全。选择CFD数值模拟法,对城市街道峡谷内燃气管线的扩散泄漏进行了分析。基于二维街道峡谷断面模型,对截断阀关闭前后燃气泄漏扩散的基本规律进行了分析研究。数值模拟结果表明,风对燃气的扩散起主导作用,街道峡谷内形成的独立而稳定的涡旋气流场会使燃气聚集并且难以扩散。

关键词: 城市燃气 , 泄漏扩散 , 数值模拟 , 街道峡谷 , 涡旋流场