不同通风方式下地铁区间隧道火灾烟气特性分析

Analysis on Characteristics of Metro Interval Tunnel Fire Smoke under Different Ventilation Modes

为了解不同通风方式下隧道火灾烟气的运移情况,开展了管道热烟实验;进行了不同通风方式下火灾烟气运移的数值模拟;分别采用理论计算和数值模拟方法得到了不同火源热释放速率的纵向临界风速。结果表明:纵向风速较小时管道中的烟气呈现层状运动,风速较大时烟气分层现象消失;车厢内烟气的温度高于车厢外相同高度的烟气温度;采用数值模拟得到的临界风速低于弗洛德临界模型的计算结果;相同火灾功率时压入式通风临界风速比抽出式通风临界风速略小。当隧道内产生速度不小于2 m/s的纵向风时,可将烟气限制在火源的下游隧道。

In order to understand the movement of the smoke in the tunnel under different ventilation modes,the smoke experiment of the pipeline was carried out,and the numerical simulation of the smoke migration under different ventilation modes was carried out.The theoretical calculation and numerical simulation were used to obtain the critical velocity of different heat release rates.The results show that the smoke in the pipeline is stratified when the longitudinal wind speed is small,and the smoke stratification disappears when the wind speed is large.The temperature of the smoke in the compartment is higher than that of the same height outside the cars.The critical velocity obtained by numerical simulation is lower than that of the froude critical model.The critical velocity at blowing ventilation mode is lower than that at the extracted ventilation in the same heat release rate.It is concluded that when the vertical velocity is no less than 2 m/s in the tunnel,the smoke can be confined to the downstream tunnel of the ignition source.