埋地天然气管道泄漏扩散数值模拟

针对天然气管道不同损伤过程中的泄漏扩散问题,利用FLUENT软件,建立CFD仿真模型,研究了泄漏口大小对天然气泄漏扩散范围的影响。以山区与城镇交界处的天然气埋地管道为例,考虑风速随高度的变化和关闭阀门后泄漏率随时间的变化,对天然气泄漏扩散进行数值模拟,编写导入FLUENT的UDF程序并对风速和泄漏率进行了修正。实例计算结果表明,扩散范围随着泄漏口的增大而变大,在泄漏口直径为6.35、25.40mm和101.60mm时,天然气爆炸下限距地面高度分别可达92、122m和408m,天然气爆炸下限下风向距泄漏口的水平距离分别可达322、770m和1 291m;由于天然气受管道上层土壤的影响而损失大量湍能,因此泄漏气体在地表和土壤中扩散时,泄漏气体在地表的扩散范围大于在土壤中的扩散范围,其中泄漏口直径为101.60mm时扩散范围最大,天然气爆炸下限下风向距泄漏口的水平距离在地表和土壤中最大分别可达80m和105m。

Numerical Simulation of Leakage and Dispersion of Natural Gas Buried Pipeline

According to different damage process of natural gas pipeline leakage diffusion problems,using FLUENT software,CFD simulation model was established,and studied the different leak diameter of the effects on gas leakage diffusion area and simulated the natural gas leak and diffusion process between mountain and city terrain.The situation of wind speed changing along with the height and mass discharge rates variable with the time were taken into account and UDFs were programmed into the FLUENT to amend them.It concluded that the bigger hold can achieve the higher range,the max lower explosive limit of the high from the ground and downwind horizontal distances of diameter of 6.35,25.40 mm and 101.60 mm were 92mand322 m,122m and 770 m,408m and 1291 m.When diffuses on the surface and in the soil,the 101.60 mm leak diameter had the maximum diffusion range.The biggest downwind horizontal distances were up to 80 mand 105m respectively.This was because the gas lost a lot of turbulent energy influenced by the soil above the pipeline.