基于FDS的居民楼火灾烟气远距离传播过程研究

利用大涡模拟软件FDS对某居民楼火灾发生发展和烟气传播过程进行数值模拟,探讨烟气质量浓度在侧间-走廊建筑的分布情况。在不同房间的目标位置设置探测点,分析烟气质量浓度、CO体积分数分布。结果表明,距离火源位置最远的房间烟气质量浓度、CO体积分数最高且在短时间内达到致死浓度;烟气更容易在最远的房间聚集,在特定的时间段内,始终比其他房间的危险性要高。对于此类居民楼建筑火灾中的人员安全而言,最远端房间的危险性最高,火灾时要着重注意此区域的疏散。此外,在走廊顶棚上间隔适当的距离设置了挡烟垂壁,并且模拟了该工况下烟气质量浓度分布。结果表明,加入挡烟垂壁后走廊的烟气蔓延相对均匀,各个房间烟气质量浓度更为接近,最大烟气质量浓度也有明显降低,从而延缓了整个建筑达到危险状态的时间。

Simulation on the smoke transport process to remote room during a residential building fire based on FDS

The present paper is aimed to introduce the basic information of residential building fire,to develop LES filed simulation software FDS in setting up a numerical simulation model of the residential building and to simulate the process of smoke movement as well as fire development.The result reveals that the speed of smoke move to other rooms was very fast as the smoke filled all of the space after 430 s.In order to analyze the soot density,some simulated detectors have been installed at some selected locations in each room.The results of our simulation demonstrate that the soot densities in center point of room S1 and N1 which were farthest from the fire room firstly reach the peak.In addition,during the fast growing of soot density,room S1 and N1 have always significantly higher soot density compared to other rooms throughout the full development stage of fire.The soot density change trends of other locations were same as the center location.Meanwhile,in order to analyze the carbon monoxide concentration,several detectors have been set up at selected locations in each room.The results of simulation show that the carbon monoxide concentration of room S1 and N1 have exceeded the lethal concentration of 0.25% at 318 s.In contrast,the carbon monoxide concentration of room S2-S7 and room N2-N7 grew more slowly than room S1 and room N1,which exceeding the lethal concentration of 0.25% at 373 s.The most remote room for this type of residential building was found to have the highest risk of fire safety,therefore the evacuation of this kind of area should be focused.Furthermore,the simulation has set smoke-proof pendant wall in the corridor roof to simulate the soot density distribution in this scene.The result reveals that the smoke movement in the corridor is relatively well-distributed where the soot densities are close to each other.It is obvious to see that the maximum soot density has been decreased,delaying the time for smoke to reach the dangerous state and improving fire safety of the building.