热障效应对有顶步行街自然排烟的影响

Influence of thermal barrier effect on natural smoke extraction of roofed pedes-trian street

为了研究热障效应对有顶商业步行街自然排烟的影响,采用理论分析与数值模拟相结合的方法,对不同高度及不同环境温度条件下有顶商业步行街自然排烟时顶棚附近的温度、能见度以及排烟效率进行了分析。结果表明:顶棚附近环境温度越高,自然排烟效果越差,自然排烟效率随顶棚热空气温度的升高呈现线性降低趋势;步行街高度越高,竖直方向的温度差越小,到达顶棚的烟气流速越小,排烟效率越低;当顶棚附近环境温度为45℃时,有顶商业步行街高度不宜超过35 m。

In order to study the influence of thermal barrier effect on natural smoke extraction of commercial roofed pedestrian street,the parameters such as temperature,visibility and smoke extraction efficiency near the roof under the conditions of different heights and environment temperatures were analyzed by using the combined method of theoretical analysis and numerical simulation. The results showed that the higher the environment temperature near the roof,the worse the natural smoke extraction effect,and the natural smoke extraction efficiency presents a linear decrease trend with the increase of hot air temperature at the roof. The higher the height of pedestrian street,the smaller the temperature difference in the vertical direction,the smaller the smoke flow velocity reaching the roof,and the lower the smoke extraction efficiency. The height of commercial roofed pedestrian street should not be more than 35 m when the environment temperature near the roof is 45℃.