室外风对高层建筑竖井内烟气运动影响的数值模拟

采用火灾模拟专业软件FDS对不同火源位置、不同风向条件下火灾烟气的运动进行模拟,测定典型位置处温度、速度、CO及CO2体积分数变化情况。实验结果表明:在近地风场中,风向对竖井内烟气蔓延的影响大小顺序为迎风>背风>侧风,竖井开口位于迎风面时,外界风对竖井内烟气运动影响最大:火源位于中性面以上时,烟气通过竖井与前室的开口向竖井内蔓延,并向下运动;而火源位于中性面以下时,前室内烟气向外部运动,竖井内无烟气流入。

Numerical simulation of the effect of outdoor wind on the smoke movement inside of high-rise building vertical shaft

There are many vertical shafts in high-rise buildings, such as stairwell,elevator shaft and pipe shaft etc.Vertical shafts are the main ways through which smoke spreads when high-rise building fire occurs.In this paper the fire smoke movement was simulated with FDS under different fire origins and wind direction conditions.At the same time,the temperature,velocity and the concentration of carbon monoxide and carbon dioxide were determined.The result shows that: the outdoor wind affected the smoke movement in shafts more than other conditions when the shaft openings were on the windward side: if the fire origin located under the neutral plane,the smoke spread outside and moved downward through the openings between shafts and atria;if the fire origin located below the neutral plane,the smoke in atria moved outside and there was no smoke in shafts.