喷头间距对城市隧道细水雾灭火的影响研究

为合理设置城市交通隧道细水雾自动灭火系统喷头间距，在实体隧道中进行了4种不同喷头间距的细水雾灭火实验，利用FDS软件模拟了8种喷头间距下细水雾对火灾温度、烟气密度的影响情况。研究结果表明:实验数据与模拟数据基本吻合；细水雾对隧道火灾抑制效果明显；喷头间距对火灾影响规律可划分为2个区域，对于Ⅰ区（间距<2.5 m），单位体积细水雾质量是影响细水雾灭火的最主要因素，对于Ⅱ区（间距≥2.5 m），细水雾灭火效果受单位体积细水雾质量、动量综合影响，并分别给出了温度、烟气密度与喷头间距的函数关系式；就宽6 m、高5 m的城市隧道而言，细水雾喷头间距宜设置为2.5 m。

Research on influence of sprinkler spacing on water mist fire extinguishing in urban tunnel

In order to rationally set the sprinkler spacing of water mist automatic fire extinguishing system in the urban traffic tunnels, the experiments of water mist fire extinguishing under the conditions of four different sprinkler spacing were carried out in the real tunnel, and the influence of water mist on the fire temperature and smoke density under the conditions of eight sprinkler spacing was simulated by using FDS software. The results showed that the experimental data were basically consistent with the simulated data, and the suppression effect of water mist on the tunnel fire was obvious. The influence of sprinkler spacing on fire could be divided into two zones. For zone Ⅰ (spacing less than 2.5 m), the mass per unit volume of water mist was the uppermost factor affecting the water mist fire extinguishing. For zone Ⅱ (spacing no less than 2.5 m), the fire extinguishing effect of water mist was synthetically affected by the mass per unit volume and momentum of water mist. The functional relationship formulas of temperature and smoke density with the sprinkler spacing were proposed respectively. For the urban tunnel with the width of 6 m and the height of 5 m, the sprinkler spacing of water mist should be set as 2.5 m.