Smoke movement in a tunnel of a running metro train on fire

Research on the distribution of smoke in tunnels is significant for the fire emergency rescue after an operating metro train catches fire. A dynamic grid technique was adopted to research the law of smoke flow diffusion inside the tunnel when the bottom of a metro train was on fire and to compare the effect of longitudinal ventilation modes on the smoke motion when the burning train stopped. Research results show that the slipstream curves around the train obtained by numerical simulation are consistent with experimental data. When the train decelerates, the smoke flow first extends to the tail of the train. With the decrease of the train's speed, the smoke flow diffuses to the head of the train. After the train stops, the slipstream around the train formed in the process of train operation plays a leading role in the smoke diffusion in the tunnel. The smoke flow quickly diffuses to the domain in front of the train. After forward mechanical ventilation is provided, the smoke flow inside the tunnel continues to diffuse downstream. When reverse mechanical ventilation operates, the smoke in front of the train flows back rapidly and diffuses to the rear of the train.

专用通气排水系统通气机理研究初探

在超高层足尺试验塔上模拟超高层排水系统,采用定流量排水方式,考察DN110PVC-U专用通气排水系统内的气流分布情况,探究排水流量的改变对通气立管内风向以及结合通气管处的风向、通气流量的影响情况。结果表明,在模拟超高层住宅排水系统中,通气立管中会出现气流方向频繁反复的楼层区域,且随着排水流量的增大该区域的位置有逐渐向下移动的趋势,处在气流方向频繁反复区域的结合通气管的平均通气流量较附近其他楼层的平均通气流量高。

结合管设置方式对专用通气排水系统通气的影响

在超高层足尺试验塔上,考察DN110 PVC-U专用通气排水系统隔层安装结合通气管工况下的气流分布情况,探究结合通气管设置方式对通气立管内风向以及结合通气管处风向、通气流量的影响情况。试验表明,在模拟超高层住宅排水系统中,隔层安装结合通气管工况下通气立管中同样会出现两处气流方向频繁反复的楼层区域,且随着排水流量的增加该区域的位置有逐渐向下移动的趋势;出现气流方向频繁反复的中部楼层区域的平均通气流量较附近其他楼层的平均通气流量更高;横支管最大正、负压均有偏向于正压的波动趋势。