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为研究浅水区域海底管道泄漏天然气扩散规律,减少重大事故的发生,基于计算流体动力学(CFD)理论,建立海底天然气管道泄漏事故后果预测和评估模型。通过用户自定义函数(UDF)给出海流流速分布情况,结合VOF模型和k-e湍流模型,实现对泄漏天然气扩散行为的模拟,研究不同泄漏速率、泄漏孔径及海流流速对天然气在海水中扩散行为的影响。结果表明:海底天然气泄漏扩散大致经历气云团→大气泡→小气泡3种形态的变化过程;泄漏速率越大,扩散气体气泡半径越大,与海水掺混比例越小,抵达海面的时间越短;泄漏孔径变化对天然气扩散的影响与泄漏速率变化影响相同,但泄漏孔径变化对天然气扩散形态的影响更为明显;海流流速越大,气体扩散轨迹与海底的夹角越小,沿海流方向的扩散距离越大。
In order to study the rule of natural gas leakage in submarine pipelines in shallow water area and reduce the occurrence of major accidents, the prediction and assessment model of the consequences of submarine natural gas pipeline leakage accidents is established based on the theory of computational fluid dynamics (CFD). The distribution of the flow velocity in the seawater is given by the user defined function (UDF). The VOF model and ke turbulence model are combined to simulate the diffusion behavior of the leaking gas. The effects of different leakage rates, leakage pore size and flow rate on the diffusion of natural gas in seawater are studied influences. The results show that the leakage and diffusion of natural gas in the seabed generally undergo the processes of gas clouds → large bubbles → small bubbles. The larger the leakage rate is, the larger the bubble radius of the diffusion gas is and the smaller the proportion is. The time to reach the sea surface The effect of leakage aperture on natural gas diffusion is the same as that of leakage rate, but the influence of leakage aperture on natural gas diffusion morphology is more obvious. The larger the current velocity, the smaller the angle between gas diffusion trajectory and seafloor, The greater the diffusion distance.