掺氢天然气长输管道泄漏扩散规律数值模拟

目的探究多因素耦合下掺氢导致的天然气长输管道泄漏扩散规律。 方法以西气东输二线工程为研究对象,采用Fluent软件建立管道二维平面泄漏扩散模型,通过单因素和多因素耦合分析掺氢比、泄漏孔径、风速和大气温度对掺氢天然气泄漏扩散的影响。 结果随着掺氢比增加,甲烷扩散区域的质量分数和宽度减小,而氢气则相反；随着泄漏孔径增大,掺氢天然气扩散的质量分数和范围增加；随着风速增加,掺氢天然气泄漏后扩散的质量分数增加,且分布逐渐向下风向偏移,而扩散高度减小；大气温度对掺氢天然气泄漏扩散的影响不显著。不同因素对掺氢天然气管道泄漏扩散范围的影响程度为:泄漏孔径＞风速＞掺氢比＞大气温度。 结论4种影响因素中,泄漏孔径对掺氢天然气管道泄漏扩散的影响程度最大,因此应重点防范掺氢天然气管道因腐蚀等因素引起的管道开裂、穿孔引起的泄漏。 

Numerical simulation of leakage and diffusion rules of hydrogen blended natural gas long-distance transportation pipelines

ObjectiveThe leakage and diffusion rules of natural gas long-distance transportation pipelines caused by hydrogen blending under multi-factor coupling are explored. Methods Taking the West-East Gas Transmission Second Line Project as the research object, Fluent software is used to establish a two-dimensional plane leakage and diffusion model of the pipeline, and the effects of hydrogen blending ratio, leakage aperture, wind speed and atmospheric temperature on the leakage and diffusion of hydrogen blended natural gas are analyzed by single-factor and multi-factor coupling. ResultsAs the proportion of hydrogen blending increases, the concentration and width of the methane diffusion region decreases, while the opposite is for hydrogen. The concentration and extent of hydrogen blended natural gas diffusion increase with the enlargement of leak aperture. With the increase of wind speed, the concentration of diffusion after the leakage of hydrogen blended natural gas increases, and the distribution gradually shifts downwind direction, while the diffusion height decreases. The influence of atmospheric temperature on the leakage and diffusion of hydrogen blended natural gas is not significant. The influence degree of different factors on the leakage and diffusion range of hydrogen blended natural gas pipeline is leakage aperture > wind speed > hydrogen blending ratio > atmospheric temperature. ConclusionsAmong the four influencing factors, the leakage aperture has the greatest influence on the leakage and diffusion of hydrogen blended natural gas pipelines. Therefore, the emphasis should be focused on preventing the leakage caused by pipeline cracking and perforation caused by corrosion and other factors of hydrogen blended natural gas pipelines.