在小尺寸长通道实验台上开展了一系列机械排烟实验,模拟了长通道内发生火灾时,通道单端开敞和双端均开敞的条件下,由于火源与排烟口相对位置不同造成的烟气层界面湍流动力学卷吸效应的差异对机械排烟效果的影响。结果表明:将排烟口设置在烟气蔓延的一维水平运动阶段时,将明显加剧烟气层界面的湍流卷吸,导致排烟效果不理想。应将排烟口设置在距火源纵向距离小于通道宽度1.33倍的范围内,单端开敞时,还应开启靠近通道封闭端的排烟口。
A series of mechanical smoke exhaust experiments were conducted in a bench-scale long channel. Two opening conditions were simulated, two ends being opened and a single end being opened respectively. The influence of the turbulent entrainment intensity at the smoke layer interface, due to different relative locations of exhaust openings to fire source, on the mechanical smoke exhaust efficiency is studied. The results show that when the exhaust openings are operated in the stage of one-dimensional horizontal spread, the turbulent entrainment effect at the smoke layer interface would be evidently intensive, leading to a poor smoke control effect. It is recommended to operate the exhaust openings in the range of the longitudinal distance to fire source less than 1.33 times of the channel width. And for the channel with one end closed, additionally exhaust openings should be opened near the closed end.