天然气长输管道泄漏工况数值模拟

Numerical simulation on leakage of long-distance gas pipeline

针对无风和有风情况下埋地天然气管道的管状扩散和渗透扩散泄漏过程建立了物理数学模型,使用Gambit软件对模型进行网格划分,运用计算流体软件Fluent进行数值模拟,研究了两种泄漏过程在不同时刻的扩散区域和安全避让区域,以及土壤渗透率对天然气泄漏扩散区域和浓度分布的影响。结果表明:天然气泄漏在有风情况下对地面扩散的影响更大,当风速增大到一定程度时,仅在泄漏口上风向存在安全区域;泄漏天然气穿过土壤层后剩余速度的大小决定了扩散高度、范围和气流形态,相对低渗透土壤,穿过高渗透率土壤层的天然气在空气中形成的扩散区域更大,扩散高度更高,但后期两者扩散范围基本相同。(图8,参10)

The physical and mathematical model is built for the tubular diffusion and infiltration diffusion leaking process of the buried gas pipeline in both windy and windless weathers. The mesh of the model is partitioned using Gambit software while the numerical simulation is conducted using Fluent, a software, to compute fluid. The diffusion region and safe avoidance region of the two kinds of leaking process at different time and also the effect of soil permeability on the leakage and diffusion region and concentration distribution of natural gas are studied. The results show that the leakage of gas in windy weather has a larger influence on the ground diffusion. In addition, when the wind speed reaches a certain degree, safe region only exists in the windward direction of the leakage point. The residual velocity of the leaking gas after permeating the soil determines the diffusion height, range and forms of gas flow. Compared with the case that gas passes through the low permeable soil, the gas passing through the high permeable soil has a larger diffusion region in the air and a higher diffusion height. However, the diffusion ranges of the two cases are almost the same in the long run. （8 Figures, 10 References）