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城市燃气管网大多埋于地下,存在很多难以探测的微小泄漏,是城市公共安全的隐患。该文面向城市地下燃气管网泄漏探测和评估的需求,针对土壤和大气中燃气扩散规律的不同,在OpenFOAM中对不同的控制方程分别进行求解,并通过地面的传质通量将土壤和大气中的扩散过程进行耦合。研究泄漏量对压强和浓度分布的影响、地面对流传质系数对浓度分布和地面传质通量的影响,计算泄漏燃气在城市街道峡谷中的分布情况。结果表明:地面传质通量分布对街道峡谷中的甲烷浓度分布影响很小,为埋地燃气管道泄漏的探测和评估提供了参考和依据。
Most of the city gas pipeline network buried in the ground, there are many small leaks difficult to detect, is the hidden dangers of urban public safety. This paper addresses the need of urban underground gas pipeline leak detection and assessment. In view of the different diffusion rules of gas in the soil and the atmosphere, different control equations are solved in OpenFOAM respectively, and the soil and atmosphere are transferred through the ground mass flux In the process of diffusion coupling. The effect of leakage on pressure and concentration distribution, the effect of ground convection mass transfer coefficient on concentration distribution and ground mass transfer flux were studied, and the distribution of leaking gas in urban street canyon was calculated. The results show that the ground mass flux distribution has little effect on the methane concentration distribution in the street canyon, which provides a reference and basis for the detection and assessment of buried gas pipeline leakage.