火灾烟气中含有多种有毒和有害成分,具有很大危害性,减少烟气危害的关键是将烟气层底面高度控制在对人员没有危害的高度。通过对大空间机械排烟的烟气流动过程进行CFD数值模拟,得出了大空间机械排烟的烟气流动性状,根据模拟结果可知,按现行设计规范,在火源释热率较大的情况下,难以将烟气层控制在理想的高度。文章建议根据火源释热率、火灾发生后的逃生时间、烟气层的控制高度合理确定大空间的机械排烟速率。 Fire smoke contains a variety of toxic and harmful ingredients, with great danger, the key to reducing the harm of flue gas is to control the height of the floor of flue gas at a height that is not hazardous to personnel. Through the CFD numerical simulation of the flue gas flow in large space mechanical exhaust smoke, the smoke flow characteristics of large space mechanical exhaust smoke are obtained. According to the simulation results, according to the current design code, In the case, it is difficult to control the flue gas layer to a desired level. The article suggests that according to the heat release rate of the fire source, the escape time after the fire and the control height of the flue gas layer, the mechanical exhaust velocity of the large space should be reasonably determined.