低温干式接头密封失效泄漏扩散数值模拟

Numerical Simulation of the Leakage and Diffusion of Methane Caused by the Sealing Failure of Low-Temperature Dry Joint

针对低温干式接头密封失效造成甲烷泄漏的情况,采用CFD软件FLACS对LNG气化后的泄漏扩散过程进行数值模拟,对甲烷扩散过程的浓度分布及云团扩散速度进行研究,并分析了泄漏过程中可燃气体云团量的变化情况。结果表明:LNG泄漏后迅速气化扩散,40 s后各监测浓度维持稳定;最远扩散距离约40 m,气体扩散总范围最长直径约70 m,扩散最高处大约1.5 m;120 s内LNG泄漏量为30 kg,气化后天然气体积为42.3 m 3,可燃气体云团量为140 m 3;LNG泄漏吸收空气中的热量,在地面形成流动层,贴近地面浓度高,远离地面浓度低,随着高度上升气体的可燃爆炸危险区域逐步缩小。

Aiming at the methane leakage caused by the sealing failure of low-temperature dry joint,the change process of methane after the leakage was numerically simulated with FLACS software by CFD.The concentration distribution and cloud diffusion velocity of methane diffusion process were studied.Results showed that the liquefied natural gas quickly vaporized and diffused after leakage,and then the methane concentration at each point remained stable after 40 s;the maximum diffusion distance was about 40 m,the maximum diameter of gas diffusion range was about 70 m,and the maximum diffusion height was about 1.5 m,the leakage amount of LNG in 120 s was 30 kg,and the volume of natural gas after vaporization was about 42.3 m 3,and the amount of combustible gas cloud was 140 m 3.LNG absorbs heat from the air and forms a flow layer on the ground,with a high concentration close to the ground and a low concentration far away from the ground.Therefore,with the rise of the height,the flammable explosion danger zone of the gas gradually shrinks.