基于CFD模拟的不同尺度竖井模型内烟气温度分布相似性的研究

通过小尺寸实验来研究实际建筑结构的火蔓延和烟气控制是一种已经被验证的十分有效的方法。经典方法中尺寸缩放只需要保证Froude数不变即可。采用CFD模拟的方法研究由火灾引起的烟气羽流在高层建筑竖井内的温度分布情况,建立三种不同尺寸高层建筑竖井的相似模型,并对比模拟结果,得出了尺寸缩放的规律:在保证Froude数不变的前提下,还需保证竖井结构内的流动为湍流;同时得到了着火房间通风口无量纲面积大小和火源位置变化对不同尺寸模型内流动相似性效果的影响规律。

Similarity study of temperature distribution in different scale shaft models with CFD simulations

In fire research, it has been validated that the fire spread and smoke control can be effectively studied by reduced-scale experiments. For use of this method, it is generally needed to keep the Froude number be constant. The present study focuses on the temperature distribution in the different scale vertical shafts, by means of a series of CFD simulations. In order to obtain the scaling law, three dimensional vertical shaft models are established. It is shown that for keeping the similarity in scaling procedure base on Froude scaling law, the Froude number should be preserved, and the turbulence level should always be ensured by comparison with the simulated results. Meanwhile, other configuration parameters such as the area of fire source, the fire position, and the ventilation conditions also influence the results of reduced-scale experiments.