海拔对隧道内列车火灾烟气蔓延特性影响

Influence of Altitude on Smoke Propagation Characteristics of Train Fire Accident in Tunnel

为探究海拔高度对隧道内列车火灾烟气蔓延的影响,基于已被验证的数值模拟方法,结合三维非定常N-S方程和RNG k-ε湍流模型,采用滑移网格技术模拟了在隧道内匀速运行的列车发生火灾后减速并最终停在隧道内的整个运动过程,并利用动模型试验和缩尺隧道火灾试验数据验证了数值模拟方法的可靠性.结果表明:海拔高度对隧道内列车停车以后的火灾烟气蔓延影响明显;与低海拔隧道相比,同一时刻高海拔隧道拱顶同一位置处的烟气流速更快,烟气逆流至火源上游50 m处的时刻更早;车体周围温度分布也随着海拔高度的不断增加而呈现出逐渐上升的趋势.与0 m海拔隧道相比,5000 m海拔隧道内烟气逆流至火源上游50 m的时刻提前了102 s,同时列车停车360 s时隧道拱顶处的温度峰值增加了216 K,增幅达到42.9%.

To investigate the influence of altitude on smoke propagation of train fire accident in tunnels,based on the validated numerical simulation method,the sliding grid technology was used to achieve the entire motion process of a train running at a uniform speed in a tunnel,decelerating after a fire accident and eventually stopping in the tunnel.The three-dimensional unsteady N-S equation and RNG k-ε turbulence model were adopted,and the reliability of the numerical simulation method was verified by the datas of the scaled train fire accident test in tunnel.The results indicate that the altitude has a significant impact on the smoke propagation after fired trains stop in the tunnel.Compared with low altitude tunnels at a time,the smoke propagation velocity at the same location as the tunnel vault is faster in high altitude tunnels,and the time when the smoke countercurrents to 50 m upstream of the fire source is earlier.The temperature distribution around the train also shows a rising trend with the increasing altitudes.Compared with the train fire accident in the tunnel at an altitude of 0 m,the time is 102 seconds earlier when the smoke in the tunnel at an altitude of 5 000 m countercurrents to 50 m upstream of the fire source.At the same time,the peak value of temperature at the tunnel vault is increased by 216 K,with an increase of 42.9% when the fired train stopped for 360 seconds.