室外风和加压送风综合驱动对防烟效果和烟气运动的影响

The Effect of the Combination Drive of Outdoor Wind and Pressurization on Smoke Control Effect and Smoke Movement

本文在相似原理基础上,开展1/3缩尺寸试验,通过改变室外风和加压送风量改变试验条件,研究了室外风和加压送风综合驱动对前室防烟效果和疏散走道烟气运动的影响。通过疏散走道烟气形态和前室门处烟气温度和气流速度等参数,定量分析了不同室外风条件下的临界送风量。试验结果表明,室外风增大时,烟气紊乱程度增大,临界送风量增大,当室外风为4.0 m/s时,烟气层完全紊乱,单独使用加压送风不能满足有效防烟。通过疏散走道各测点的烟气温度,分析了室外风和加压送风对烟气层高度和烟气温度的影响。试验结果表明,当加压送风量一定时,室外风增大会导致烟气层高度下降和烟气温度升高。当室外风一定时,送风量增大会导致烟气层高度升高,但当送风量大于前室5000 m^3/h、楼梯间10000 m^3/h时,加压送风会导致前室门附近烟气层高度下降;送风量越大,烟气温度越低。

1/3 scale experiment was carried out in this paper to investigate the smoke control effect of atria and smoke movement in evacuation walk under the combination drive of outdoor wind and pressurization on the basis of similitude principle,by means of changing the outdoor wind size and pressurized air supply rate.The critical air supply rate under different outdoor wind conditions was analyzed quantitatively through the smoke pattern in the evacuation walk and gas temperature and airflow velocity at the door of atria.The results showed that the degree of smoke disorder and the critical air supply rate increased with the increase of outdoor wind velocity,the smoke layer was completely disordered and it could not meet the requirement of effective smoke prevention if use pressurization alone when the outdoor wind velocity reached 4.0 m/s.The effect of outdoor wind and pressurization on smoke layer height and smoke temperature was analyzed through the temperature of measuring point in the evacuation walk.The results showed that the smoke layer height fell and the smoke temperature increased with the increase of outdoor wind velocity when the rate of pressurized air supply was constant.The smoke layer height increased with the increase of pressurized air supply rate when the outdoor wind velocity was constant,but pressurization would lead to the fall of smoke layer height around the door of atria when the rate of pressurized air supply larger than 5000 m^3/h of atria and 10000 m^3/h of staircase;the smoke temperature decreased with the increase of pressurized supply air rate.