封闭式中庭火灾排烟实验与模拟分析

Experimental and numerical study on fire-smoke movement in enclosed atrium

以某62m高封闭式中庭为对象,建立了火灾排烟盐水模型实验台,用盐水和清水密度差导致的水流运动模拟实际建筑中热烟气与冷空气之间密度差导致的热羽流的运动。利用FDS软件对实际火灾时烟气的运动情况进行了模拟。模拟结果和实验结果的比较表明,盐水实验虽然忽略了探测器达到探测阈值的时间延迟及竖壁冷对流的影响,但对热分层高度和达到稳定时间的预测偏差很小。在1 MW火灾规模下,利用盐水实验方法对该封闭中庭火灾烟气运动规律和排烟系统设置进行评价分析是可行的。

Establishes a salt-bath experimental system to study the indoor fire-smoke movement in a 62 meter high enclosed atrium.Smoke movement driven by the thermal plume by the density difference between thermal smoke and cold air in the prototype building is modeled by water flow movement by the density difference between brine water and fresh water in the scaled model.Simulates the smoke movement in actual fire situation with the FDS software.The comparison of the simulation and the experiment results shows that though the salt-bath experiment ignores the effect of both the time lag by the smoke detector and the cooling convection along the atrium wall,the prediction deviations of thermal stratification height and the time to stabilization state are small.For a fire with the intensity of 1 MW,it is practicable to apply the salt-bath experimental method to predict the fire-smoke movement characteristics in the enclosed atrium and estimate the performance of the exhaust system.