The combustion characteristics of multisource fire and single‐source fire are quite different, and there is little research on the influence of multisource fire on the natural smoke extraction effect of shaft in urban tunnels. Therefore, in this article, the method of numerical simulation was used to study the influence of fire power and distance between two fire sources on the natural smoke extraction effect of shaft and the temperature distribution in tunnel in the case of multisource fire. Typical characteristics of smoke are analyzed, such as mass flow rate, temperature distribution, velocity vector, and CO concentration. The simulation results show that when there is a certain distance between the fire sources, the two flames are inclined and close to each other. The smoke temperature under the ceiling is higher under multiple fire sources than that under single fire source. In addition, when one of the fire sources is located at the downstream of the shaft, the smoke emission in the shaft is relatively high. As the distance between fire sources continues to increase, the smoke exhaust rate basically remains stable, and an empirical relationship between smoke exhaust rate and fire source location is established.

中文翻译：

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多源火对城市竖井隧道温度分布和自然排烟效果的影响

多源火与单源火的燃烧特性差异很大，关于多源火对城市隧道竖井自然排烟效果影响的研究很少。因此，在本文中，采用数值模拟的方法研究了火源功率和两个火源之间的距离对多源火情况下竖井自然排烟效果及隧道温度分布的影响。分析了烟雾的典型特征，例如质量流量，温度分布，速度矢量和CO浓度。仿真结果表明，当火源之间有一定距离时，两个火焰是倾斜的并且彼此靠近。在多个火源下，天花板下方的烟气温度比在单个火源下更高。另外，当火源之一位于竖井的下游时，竖井中的烟尘排放量相对较高。随着火源之间距离的不断增加，烟气排放率基本保持稳定，烟气排放率与火源位置之间建立了经验关系。