在建建筑火灾轰燃数值仿真研究

为研究在建建筑特殊火灾的轰燃现象，建立火灾能量守恒方程，基于燕尾突变理论确定突变势函数，计算出在建建筑火灾轰燃时上层烟气的临界温度。利用模拟软件FDS对在建建筑不同施工场景进行仿真模拟，得到火灾特征参数值。结果表明：不同施工阶段的火灾可燃物不同，发生轰燃的时间点不同；随着通风风速的增加，火灾热释放速率增长逐渐放缓，烟气可见度增长加快，一定的通风速度有助于提高排烟效率；不同火源位置火灾特征不同，狭窄空间更容易发生轰燃，未封闭楼梯间处烟囱效应明显。

Numericial simulation of fire flashover in building under construction

In order to study flashover phenomenon of special fire in building under construction, a fire energy conservation equation was first established in this paper. Then,the critical temperature of thermal smoke during the flashover was determined by the catastrophe potential function based on the swallowtail catastrophe theory. Finally, the software FDS was adopted to simulate the fire flashover considering different construction scenarios, so that the corresponding fire characteristic parameters can be obtained. The results show that different fire combustible materials at different construction stages lead to different flashover time points. With the increase of ventilation velocity, the rate of fire heat release increases slowly, whereas the visibility of smoke increases rapidly. In addition, the fire characteristic parameters are highly related to the fire sources. Thus, flashover is more likely to occur in narrow space, leading to an obvious chimney effect, especially for the unclosed stairwell.