天井顶棚高度对自然排烟影响的数值模拟

Numerical simulation of patio ceiling height effect on natural smoke evacuation

为研究架空顶棚天井的架空高度对自然排烟效果的影响,以某典型商业建筑天井为研究对象,利用火灾场模拟软件FDS模拟计算了不同顶棚架空高度和不同环境风速下的烟气蔓延扩散情况。结果表明,在顶棚架空高度低于2 m时,排烟效果不理想,架空高度超过4m时,绝大部分烟气都将通过顶棚蔓延扩散出去,但天井内烟气中性面也将随之降低,随着环境风速的增加,烟气沉降将有所加剧,中性面稍有下降。计算结果将为类似建筑的设计提供可参考的思路:顶棚架空高度不宜低于2m,且应尽量减少架空区域墙体、柱体面积,为确保排烟效果,实际设计的天井高度不应过高。

In order to investigate the influence of patio ceiling height on natural smoke evacuation, with the example of a typi- cal patio in commercial building, smoke evacuation under differ- ent ceiling height and environment wind velocity were calculated by FDS. The result showed that smoke evacuation effect was not ideal with ceiling height lower than 2 m. But most smoke could be evacuated with lower neutral plane height while ceiling height higher than 4 m. While the environment wind speed in- creased, smoke subsidence would aggravate with lower neutral plane height. The results in this paper could be used in the de- sign of building with patio, for example, the ceiling height ought to be higher than 2 m and the area of wall and pillar should be decreased, at the same time, patio should be lower.