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吸穿现象的发生将降低隧道集中排烟效率。排烟口间距是影响烟气层吸穿的重要因素。以长22 m的1∶20缩尺寸集中排烟隧道模型为数值模拟研究对象。采用对称方式开启6个排烟口进行双向均衡排烟模式。比较了排烟口间距分别为3 m和2 m时的烟气蔓延范围、烟气层温度和厚度,分析了烟气层厚度、温度与排烟速率之间的关系。结果表明:排烟速率大到一定程度时会导致烟气层吸穿;排烟口间距越大,导致排烟口开始发生吸穿的排烟速率越小;同一排烟速率下,排烟口之间的间距越大,越远离火源的排烟口越容易发生吸穿。因此,为避免吸穿现象的发生,需选取合适的排烟速率及排烟口间距。
The occurrence of suction will reduce the tunnel smoke concentration efficiency. Exhaust port spacing is an important factor affecting the flue gas layer suction. A 1:20 scale-sized centralized exhaust tunnel model with a length of 22 m was used as a numerical simulation object. Symmetrical way to open the six exhaust port bidirectional balanced exhaust mode. The range of flue gas spread, flue gas layer temperature and thickness were compared when the exhaust port spacing was 3 m and 2 m respectively. The relationship between flue gas layer thickness, temperature and flue gas emission rate was analyzed. The results show that when the smoke exhaust velocity reaches a certain level, it will lead to the flue gas layer to get through. The larger the exhaust flue opening, the smaller exhaust flue gas velocity will lead to the exhausting. At the same flue gas velocity, The greater the distance between the more away from the source of smoke outlet more prone to inhalation. Therefore, in order to avoid the occurrence of suction phenomenon, we must select the appropriate exhaust velocity and exhaust port spacing.