火灾时隧道火风压及其对通风影响的试验研究

Experimental Study of Fire Pressure and Its Impact on Tunnel Ventilation

借助大比例火灾模型试验,研究了火灾工况下隧道内压力场的发展变化状态及火风压产生的机理,分析了通风速度、火灾规模、隧道坡度和烟流蔓延长度等对火风压的影响规律,以及火灾对隧道通风系统的影响.试验结果表明:火风压随着上述影响因素的增大而单调增大,但增长速率减缓;同时,火灾引起的火风压会极大地影响隧道的正常通风.建议对于长大隧道,发生火灾时,应及时将烟流的蔓延长度控制在尽可能短的范围内,以便减弱火风压对通风系统的影响.

This paper presents the results of an experimental study of the fire impact on tunnel ventilation. The scopes of the research involve： a） the behaviors of the air pressure field in tunnel fire, b） the mechanism of fire pressure, c） the influences of longitudinal forced ventilation velocity, fire load, slope gradient of tunnel and the length of smoke propagation on fire pressure, and d） the impact of fire pressure on tunnel ventilation. The experiments were conducted on the basis of 100 meter long reducedscaled model tunnels with circular cross-sections. The results show that the value of fire pressure increases as the value of the above-mentioned factors increases, but its increase rate decreases. Furthermore, the tunnel ventilation is profoundly influenced by fire pressure. Conclusions of this experiment suggest that controlling propagation of smoke is all-important in tunnel fire in order to lighten the fire impact on tunnel ventilation.