基于稳定风场的埋地天然气管道泄漏数值模拟

针对目前城镇埋地管道天然气泄漏研究模拟工况简单、可信性较低等问题，考虑障碍物对环境风场的影响，利用计算流体力学（CFD）软件建立天然气管道三维泄漏模型，将模拟过程分为环境风场的稳态模拟和管道泄漏扩散的瞬态模拟两步，分析天然气泄漏扩散规律。结果表明:在风场稳态模拟中，建筑物附近风场受干扰明显，上游形成小范围的低速滞留区，下游形成较长的尾迹。在天然气泄漏扩散瞬态模拟中，土壤层天然气受风速影响较小，气体在近地面及贴近建筑物侧积聚，扩散范围随时间逐渐趋于稳定，泄漏扩散达到稳定后表现出土壤层积聚、气云沉降、贴近建筑物积聚、气云扩散局限性的特征。风速主要影响天然气的扩散高度，对水平方向的扩散范围影响较小，风速与天然气扩散高度成反比。

Numerical simulation on leakage of buried gas pipeline based on stable wind field

Aiming at the problems such as the simpler conditions and lower credibility in numerical simulation on gas leakage of buried pipeline, considering the influence of obstacles on environmental wind field, a three-dimensional model for leakage of natural gas pipeline was established by using CFD software. The simulation process was divided into two steps, including the steady-state simulation of environmental wind field and the transient simulation of natural gas leakage and diffusion, and the laws of gas leakage and diffusion were analyzed. The results showed that in the steady-state simulation of wind field, the wind field near the building is obviously disturbed. A low velocity stagnation region with small range is formed on the upstream, and a long wake is formed on the downstream. In the transient simulation of natural gas leakage and diffusion, the gas in soil is less affected by the wind speed. The gas accumulates near the ground and building, and the diffusion range gradually stabilizes with time. When the leakage and diffusion is stable, the features such as accumulation in soil, gas cloud settlement, accumulation near the building and gas cloud diffusion limitations are presented. The wind speed has much greater impact on the diffusion height of gas and less influence on the horizontal range of diffusion, and it is inversely proportional to the diffusion height of gas.