关键词: 天然气, 埋地管道, 泄漏, 建筑物, 数值模拟

Abstract: Aiming at the process on leakage of buried gas pipeline in urban area, and considering gas of different constituents and concentration leakage based under multi building condition, using computational fluid dynamics (CFD) software to establish the three-dimensional physical model of buried pipeline in the leakage process, the environmental wind field and leakage rate into the boundary conditions in the form of user-defined functions were introduced, and the simulation process was divided into steady-state simulation in environmental wind field and transient simulation in leakage. And the leakage process was divided into continuous leakage and leakage after pipe valve closing, and the gas leakage rules were analyzed. The results showed that: It was necessary to simulate the steady state in environmental wind field. There existed three low velocity zones near the flow field and a large velocity gradient on the edge of the building. It showed the following characteristics that the confined leakage of oil layer diffusion, low velocity zone upstream gathering, gas cloud rising, hydrogen sulfide deposition and diffusion and so on in the gas continuous leakage stage. It showed the characteristics of the gas diffusion continuity and dissipation from top to bottom in the valve closed stage. Based on the conditions above, comparing methane, hydrogen sulfide had larger diffusion range, later dissipation time, and greater risk.

Key words: Natural gas, Buried pipeline, Leakage, Building, Numerical simulation