The transportation of hazardous gases such as natural gas and hydrogen through buried pipelines is widely considered the most economically safe method. In recent years, due to the extension of service time and material aging, gas leakage incidents have become more common during transportation, leading to significant hazards such as fires and explosions. This paper aims to study the leakage and diffusion behavior of buried pipelines, help emergency personnel more accurately determine the areas that may be affected, and provide theoretical support for risk assessment and emergency planning of natural gas pipeline leaks. In this paper, the influence of different factors on the diffusion law of gas leakage is analyzed, and the factors that have the greatest influence on the diffusion are obtained through exploratory data analysis. Findings reveal pressure, leak size and soil temperature are positively correlated with methane concentration and dangerous area. Conversely, soil moisture negatively correlates with methane concentration and lateral diffusion distance. Soil type significantly impacts methane concentration, with sand facilitating the most diffusion, followed by loam, and least in clay. Therefore, soil compaction is recommended to mitigate gas diffusion rates during leaks, reducing hazardous zone extents. Additionally, the study delves into the emerging trend of transporting natural gas blended with hydrogen. Higher hydrogen ratios result in quicker reaching of Lower Explosive Limit and larger hazardous zones. In order to study the complex dynamics of multi-source leakage scenarios, two pipeline leakage diffusion simulations are carried out in this paper. The results showed increased horizontal spacing reduces maximum methane concentrations on the surface. However, this also enlarges gas alert and hazardous zone areas, heightening the risk of explosion-related incidents. These conclusions provide a theoretical framework for risk assessment and emergency treatment of pipeline leakage.

中文翻译：

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基于CFD的天然气泄漏扩散特性研究

通过埋地管道输送天然气和氢气等危险气体被广泛认为是最经济安全的方法。近年来，由于使用时间延长、材料老化等原因，运输过程中燃气泄漏事件屡见不鲜，引发火灾、爆炸等重大危险。本文旨在研究埋地管道的泄漏和扩散行为，帮助应急人员更准确地判断可能受影响的区域，为天然气管道泄漏风险评估和应急预案提供理论支撑。本文分析了不同因素对瓦斯泄漏扩散规律的影响，通过探索性数据分析得出对扩散影响最大的因素。研究结果显示压力、泄漏尺寸和土壤温度与甲烷浓度和危险区域呈正相关。相反，土壤湿度与甲烷浓度和横向扩散距离呈负相关。土壤类型显着影响甲烷浓度，沙土最有利于扩散，其次是壤土，粘土最少。因此，建议压实土壤以减轻泄漏期间的气体扩散速率，从而减少危险区域范围。此外，该研究还深入研究了运输天然气与氢气混合的新兴趋势。较高的氢比率导致更快达到爆炸下限和更大的危险区域。为了研究多源泄漏场景的复杂动态，本文进行了两次管道泄漏扩散模拟。结果表明，水平间距的增加降低了表面的最大甲烷浓度。然而，这也扩大了气体警报和危险区域区域，增加了爆炸相关事件的风险。这些结论为管道泄漏风险评估和应急处理提供了理论框架。