海底输气管道气体泄漏扩散模拟及影响因素研究

为研究泄漏孔径、泄漏点水深以及外部风速对海底输气管道泄漏后果的影响,以某海底输气管道为研究对象,选取两种泄漏孔径,两种泄漏水深,9种风速进行泄漏扩散的模拟计算。计算包含泄漏模拟、气体水中扩散计算及气体在空气中扩散的CFD模拟。最终得到各泄漏工况条件下可燃气体云团体积及影响范围。通过对数据进行归纳分析,得到气云扩散及影响距离的变化规律。结果表明,泄漏速率和泄漏水深会影响海底管道泄漏后气体到达海面的气体释放面积和气体垂直流速,进而影响气云在海面的扩散后果,风速会影响气云扩散的范围和浓度分布。泄漏孔径、泄漏点水深以及外部风速是进行海底管道泄漏扩散分析的关键因素,需要在分析中进行系统性考虑以全面反映海底管道的风险水平。当前分析方法能够较全面地分析以上关键因素对后果的影响,为现场抢险、应急响应等提供判据和输入,有助于完善应急准备分析和制定更加有针对性的应急处置方案。 

Simulation of the subsea gas pipeline leakage and the study of influence factors

In order to study the influence of the leak hole size, the water depth of the leak position and the wind speed on the consequence of subsea gas pipeline release, a series of simulations are performed for a subsea gas pipeline. Two leak hole sizes, two water depths and nine wind speeds are chosen in the simulations. The calculations include leak simulation, gas dispersion simulation inside water and the gas dispersion simulation in the air. Finally, the volumes and effect distances of flammable gas cloud are calculated for each leak scenario and the study of the gas cloud volume and effect distance as a function of the influence factors are performed through data induction and analysis. Results show that leak rates and water depth of the leak position will determine the gas release area and the vertical gas velocity at the sea surface, which further influence the consequence of gas dispersion in the air. The wind speeds will influence the gas cloud volume and concentration. Leak hole size, water depth of the leak position and wind speed are important factors for the subsea pipeline leak analysis, which should be considered systematically in the analysis to fully represent the risk level of the subsea pipeline. The used method could comprehensively analyze the influence of these factors on the consequence, and provide relevant information and inputs for the on-site rescue and emergency response, which is helpful for the emergency preparedness analysis and development of targeted emergency response plan.