火源—竖井间距对自然通风隧道火灾烟气流动特征的影响

通过数值计算，研究顶部开口自然通风隧道火灾火源–竖井间距对烟气流动特征与竖井排烟效率的影响。考虑因素有火源–竖井间距、竖井断面尺寸。结果表明：随着火源–竖井间距的增大，竖井前方来流烟气的质量流量增大，且竖井的排烟效率逐渐降低，竖井内空气卷吸量减少；当火源–竖井间距较小时，竖井更有利于排出更多的热量，竖井后方的温度降低幅度更大，烟气可以被控制在更小的范围内。此外，随着竖井截面尺寸的增大，竖井的排烟效率增加，且增大竖井的宽度更有利于增加竖井的排烟量。因此建议当相邻竖井的间距较大时，可适当增加竖井的截面尺寸和竖井高度。

Impact of the fire-shaft distances on the smoke flow properties in naturally ventilated tunnel fires

The impact of fire-shaft distance on the smoke flow properties and smoke exhaust efficiency in naturally ventilated tunnel fires was studied by numerical simulations. The fire–shaft distance and the cross-section of the shaft are taken into consideration. The numerical simulation results indicate that with the increase of the fire-shaft distances, the mass flow rates of the incoming smoke before the shaft increase, however the smoke exhaust efficiency and air entrainment of the shaft decrease. Besides, when a small fire-shaft distance is employed, more heat can be exhausted and lower temperatures downstream the shaft can be generated, and the smoke can be controlled within a small range. Moreover, as the shaft cross-section increases, the smoke exhaust efficiency of the shaft becomes great and more smoke can be exhausted under a wider shaft. From the resulted obtained in this work, when a large interval of adjacent shafts is set, it is suggested that a large shaft cross-section and a large shaft height be used.