竖井送排式通风隧道火灾温度分布特征模型试验研究

Study on smoke temperature distribution based on model test in highway tunnel by shaft blow and exhaust ventilation

通过竖井送排风式纵向通风方案下的小尺度(1:50)隧道火灾模型试验,研究火灾时隧道拱顶及火源前后隧道中心线不同高度处的温度分布特征。试验结果表明:风机启闭状态对隧道拱顶各测点最高温度的影响明显;火灾发生在短道时,正常运行时1号热电偶树上各测点温度自上而下温度依次升高,温度整体较低,关停工况下时则相反,关停工况时烟气未下降至3号热电偶树底部;火灾发生在进口端时,关停工况时火源向下传递热量的能力略微下降;火灾发生在出口端时,正常工况时1号热电偶树各点温度特征规律性较差,而关停状态时较好,送风轴流风机对出口端火灾的影响更大。基于温度分布特征及试验中观察到的火灾烟气蔓延规律,建议了分水岭隧道火灾时的洞内风流组织。

To investigate the maximum temperature along tunnel ceiling and temperature distribution properties at different height of tunnel center line, a series of fire tests under the longitudinal ventilation by the blowing and exhausting shaft were conducted in a 1:50 small scale model tunnel. The results show that the fan switching state has an obvious impact on the maximum temperature along tunnel ceiling; when the fire occurs in short section, the temperature of each measure point on 1# thermo element tree rises successively from top to bottom under normal operation, and the temperature are overall lower, but the temperature situation is opposite under the condition that part of fans is off. Under shutdown condition, the smoke doesn't sink to the bottom of 3# thermo element tree; when fire occurs near tunnel entrance, the transfer capacity of fire heat decreased downward slightly under shutdown condition; when fire occurs near tunnel exit, the temperature characteristics of each point on 1# thermo element tree is in poor regularity, but that is good under shutdown condition. The axial fan to supply wind has the greater influence on smoke movement; Based on the temperature distribution and the smoke rule observed in tests, the effective airflow organization is suggested for fire fighting in Fenshuiling tunnel.