以深圳共同沟为研究对象,用甲烷代替天然气,采用向上和水平两种管道泄漏口开口方向,通过k-ε湍流模型利用FLUENT软件数值分析沟内甲烷泄漏的扩散过程,得到甲烷摩尔组分浓度的分布,并对甲烷在共同沟内的扩散特征进行详细分析.根据燃气爆炸下限浓度,将部分计算的莫尔组分浓度分布转化为探头报警时间,并同试验测定的报警时间进行对比,结果表明数值分析的精度基本令人满意.该数值分析的结果为共同沟安全设计中报警探头布置提供了重要的参考. Taking methane in Shenzhen as the research object, methane was used as a substitute for natural gas, and the upward and horizontal opening directions were used. The k-ε turbulence model was used to numerically analyze the diffusion process of methane leakage in the trench. The molar concentration of methane , And the diffusion characteristics of methane in the common trench were analyzed in detail.According to the lower limit of gas explosion concentration, part of the calculated Moiré concentration distribution was transformed into probe alarm time, and compared with the test alarm time, the results The results show that the accuracy of numerical analysis is basically satisfactory.The results of numerical analysis provide an important reference for the arrangement of alarm probes in the common ditch safety design.