横截面形状和坡度对隧道火灾烟气分布影响研究

Influence of cross-section shape and slope on smoke spread in tunnel fires

通过数值模拟建立了7种不同横截面形状的全尺寸跨座式单轨隧道模型,研究隧道横截面形状和坡度对隧道火灾烟气蔓延的影响。研究发现长方形隧道顶部温度普遍较高,其次为带有拱顶的隧道,正方形隧道顶部温度普遍较低,圆形隧道底部温度最低。在大火源功率条件下,坡度对临界风速的影响较小。离火源较远的位置,坡度对排烟效果的影响更加明显:随着坡度增加,上坡向控制风速明显降低,下坡向控制风速缓慢提升。

Seven full-size straddle monorail tunnel models with different cross-section shapes were established through numerical simulation.It was found that the ceiling temperature in the rectangular tunnels was generally higher,followed by tunnels with vaults,and the ceiling temperature in square tunnels was generally lower.The temperature at the bottom of the circular tunnel was the lowest among all the tunnels.Under the condition of large fire power,the slope had little effect on the critical wind speed.However,the effect of slope on the critical wind speed was more obvious far from the fire source:with the increase of slope,the control wind speed in the uphill direction decreased significantly,while it increased slowly in the downhill direction.