地下车库火灾烟气扩散规律的数值计算与实验

为了准确预测火灾烟气运动情况，基于SGS湍流模型与大涡模拟相结合的方法预测地下车库中火灾烟气运动规律，采用简单化学反应模型处理地下车库中小汽车火灾的复杂燃烧过程，采用P-1模型计算烟气运动过程中的热辐射传递。设定了5种不同的计算工况，采用数值计算的方法得出火场烟气、温度分布情况；对其中的部分工况进行了实体火灾实验，并与计算结果相对比。研究结果表明:开启机械排烟比只依靠自然排烟时火场温度上升快，但是在稳定燃烧阶段温度相对较低；当火源功率为2MW时，仅依靠自然排烟时火场能见度为2m，当火源功率为4MW时，考虑机械排烟时火场能见度为10m，低于规定值；数值计算和实验结果一致性较好，说明采用的计算模型合理。

Numerical calculation and experimental study on laws of smoke diffusion in underground garage fire

In order to accurately predict the movement situation of fire smoke, the method combining SGS turbulent model with large eddy simulation was adopted to predict the laws of smoke diffusion in underground garage fire. The simple chemical reaction model was applied to deal with the complex combustion process of car fire in underground garage, and the P-1 model was applied to calculate the thermal radiation transfer in smoke movement process. Five different calculation conditions were set, and the distribution situation of smoke and temperature in fire scene was obtained by using numerical calculation method. The full scale fire expements were conducted on some of the conditions, and the results were compared with the calculation results. The results showed that the fire tempreture with mechanical smoke extraction rised faster than that with only natural smoke extraction, but the tempreture in the stable combustion stage was relatively lower. When the power of fire source was 2 MW, the visibility in the fire scene was 2 m with only natural smoke extraction. When the power of fire source was 4 MW, the visibility in the fire scene was 10 m with mechanical smoke extraction, which was less than the specified value. The consistence between the results of numerical calculation and experiment was better, which indicates the proposed calculation model is reasonable.