巷道火灾密闭过程中烟气温度及流动特性研究*

为研究巷道火灾密闭过程中烟气的温度变化规律及流动特性，通过缩尺寸实验台和FDS数值模拟软件对12.65，18.97，25.30 kW不同火源功率及25%，50%，75%，100%不同密闭比例条件下的巷道火灾进行模拟实验。结果表明:密闭比例的增加会使火焰倾角减小，当巷道完全密闭后，火焰形状近似垂直，顶板热辐射和温度增加；巷道在50%和75%密闭比例之间存在1个突变值，当超过此突变值后，顶板温度会急剧升高，同时燃烧会更快进入衰减阶段，且火源功率越大衰减越早；密闭比例的增加会导致烟气逆流长度上升，增加纵向通风速度可有效地抑制烟气逆流现象，当实际巷道火源功率为4 MW时，纵向通风风速设定为3.8 m/s能使烟气逆流得到较好的控制。

Study on temperature and flow characteristics of smoke during sealing process of roadway fire

In order to study the temperature change laws and flow characteristics of smoke during the sealing process of roadway fire,the simulation experiments of roadway fire under the conditions of 12.65 kW,18.97 kW,25.30 kW fire source power and 25%,50%,75%,100%sealing ratios were carried out through the scale-reduced test bench and FDS numerical simulation software.The results showed that the increase of sealing ratio would reduce the flame inclination angle,and when the tunnel was completely sealed,the flame shape was approximately vertical,the heat radiation and temperature of the roof would increase.There existed a abrupt value between the sealing ratio of 50%and 75%in the roadway,and when exceeding this abrupt value,the temperature of roof would rise sharply,the combustion would enter the decay stage faster,and the greater the fire source power,the earlier the decay.The increase of sealing ratio would increase the length of smoke backflow,and increasing the longitudinal ventilation speed could suppress the phenomenon of smoke backflow effectively,when the actual roadway fire source power was 4 MW,setting the longitudinal ventilation speed to 3.8 m/s could make the smoke backflow get better control.