【摘要】 为了研究综合管廊内液氮的灭火效果，搭建了一个缩尺寸综合管廊液氮灭火实验平台，通过分析注入管廊后的液氮与火焰相互作用以及火源附近温度和氧气浓度的变化来研究液氮的灭火效果。结果表明：液氮的灭火过程是冷却降温和隔氧窒息共同作用的结果，其中隔氧窒息占主导作用。同时，液氮释放距离越长，灭火时间越长，液氮对火源的抑制效果越弱，但对火焰区域的气体扰动越强，0 m处注氮较4 m处注氮灭火效率提升49%。此外，当液氮释放距离在一定范围内时，垂直注氮的灭火效能优于水平注氮，0 m处垂直注氮灭火效率较水平注氮提升18.7%，随着液氮释放距离的增加，二者的差距逐渐减小。因此，精准探测火源位置，优化注氮方式，可达到最佳的灭火效果。更多还原

【Abstract】 In order to study the fire extinguishing effect of liquid nitrogen in the utility tunnel, an experimental platform for liquid nitrogen fire extinguishing in a medium-sized utility tunnel was established. The fire extinguishing effect of liquid nitrogen was studied by analyzing the interaction between liquid nitrogen and flame after injection into utility tunnel and the changes of temperature and oxygen concentration near the fire source.The results show that the fire extinguishing process of liquid nitrogen is the result of cooling and inerting, inerting plays a leading role. At the same time, the greater the liquid nitrogen release distance, the longer the fire extinguishing time, the weaker the suppression effect of liquid nitrogen on the fire source and the stronger the gas disturbance in the flame area. The fire extinguishing efficiency of nitrogen injection at 0 m is 49%higher than that at 4 m. In addition, when the liquid nitrogen release distance is within a certain range, the fire extinguishing effect of vertical nitrogen injection is better than that of horizontal nitrogen injection. The fire extinguishing efficiency of vertical nitrogen injection is 18.7% higher than that of horizontal nitrogen injection at 0 m. With the increase of liquid nitrogen release distance, the difference between the two nitrogen injection methods gradually decreases. Therefore, accurate detection of fire source location and optimization of nitrogen injection mode can achieve the best fire extinguishing effect.更多还原