LNG储罐区围堰对天然气泄漏扩散影响的数值模拟

以液化天然气(LNG)储罐区出现泄漏事故时天然气的扩散行为为研究对象,利用计算流体力学软件FLUENT为工具,建立三维非稳态仿真模型,研究了0.8 m,2.0 m和3.0 m 3个围堰高度分别在无风条件和有风条件下对天然气泄漏扩散过程的影响机制。结果发现,无风时天然气在围堰区内的扩散基本稳定后,离泄漏源最远处的围堰上天然气浓度更高,该处的围堰更容易被气云翻越。围堰高度增大,限制了天然气水平方向的扩散及削弱风场的影响,减小对围堰外区域的危害但不利于天然气的消散,合理围堰高度在0.8～2.0 m之间。

Numerical Study on Effects of the Dike in LNG Storage Tank on the Leakage and Diffusion Characteristics of Natural Gas

The leakage and diffusion behaviors of natural gas are investigated in the condition of the occurrence of the leakage of liquefied natural gas(LNG)in the storage tank.Computational fluid dynamics software,FLUENT,is adopted to simulate the process in three-dimension transient calculations.The effects of various height of the dike,0.8 m,2.0 m and 3.0 m,on the diffusion process of natural gas in windless or windy condition are investigated.The results show that after the diffusion of the gas becomes stable,the farthest roof of the dike away from the leakage source will suffer higher concentration of natural gas and more risk of gaseous escape in windless condition.In addition,higher dike benefits the resistance of horizontal diffusion of LNG and weakens the influence of the wind,reducing the hazardous level for the area outside the dike.However,it goes against the dispersion of the gas.Rational suggestion on the height of dike is in the range of 0.8 m to 2.0 m.