隧道内不同间距双火源火灾试验及模拟研究

为了给隧道双火源事故中的人员疏散和应急救援提供参考，研究隧道内部双火源火灾条件下的燃烧行为和火场环境，搭建1∶10缩尺寸模型隧道，开展不同火源间距下的双火源油池火试验，研究燃烧速率、火焰形态和隧道内纵向温度分布；同时，采用PyroSim数值模拟的方法分析隧道内部双火源之间距底面高度0.1、0.15 m处的温度分布。试验结果表明：对于隧道内双火源火灾，燃烧速率受火源间距影响较大，当间距从2D(D为油盘边长)增加到8D时，燃烧速率从20.43 g·m^-2·s^-1下降至15.61 g·m^-2·s^-1，并逐渐接近单火源燃烧速率；燃烧过程中火焰相互倾斜，倾角会随着间距增加逐渐减小，由18.3°减小至13.7°。由于两火源之间相互限制，火源之间区域内的热量不断积聚，双火源间近顶板温度明显偏高；双火源外侧远端近顶板处纵向温度呈指数衰减规律，与单火源远端顶板温度分布规律保持一致，但温度衰减因子会随着双火源间距的增加逐渐变大。数值模拟结果表明：双火源之间温度分布呈现出凹形分布规律，随着距火源距离的增加，温度迅速下降，后逐渐保持稳定，但稳定区间内的温度仍然较高，会对人员造成伤害。双火源间距对火源之间的温度分布影响较大，随着间距增加，双火源之间的稳定温度逐渐下降，对人员疏散影响逐渐变小。双火源之间温度分布规律研究结果可为火灾初期被困人员的施救提供参考。

Experimental and Simulation Study on Double Fire Source Tunnels with Different Spacings

To study the fire behavior of tunnels with dual fire sources, a dual-fire source oil pool fire experiment was carried out at different spacings. The characteristics of the flame combustion behavior and the longitudinal temperature distribution in the tunnel were studied. Meanwhile, the PyroSim numerical simulation (FDS) method was used to study the temperature distribution at the heights of 0.1 m and 0.15 m between the two fire sources inside the tunnel. The experimental results show that for a dual fire source fire in a tunnel, the burning rate is significantly affected by the distance between the fire sources. As the distance was increased from 2D to 8D, the burning rate decreased from 20.43 g·m^-2·s^-1 to 15.61 g·m^-2·s^-1, and became close to the burning rate of a single fire source. The flames were inclined toward each other during the combustion process, but the inclination angle gradually decreased with an increase in the distance from 18.3° to 13.7°. Owing to the mutual restriction between the two fire sources, the heat in the area between the fire sources continued to accumulate, and the temperature near the roof between the two fire sources was obviously higher. The temperature distribution was consistent with that of the far end of a single fire source, and the longitudinal temperature near the roof at the far end fire source of the dual fire sources showed an exponential decay law. The temperature attenuation factor gradually increased with an increase in the fire source distance. Numerical simulation results show that the temperature distribution between the two fire sources presents a “concave” distribution law. If the fire source is far away, the temperature drops rapidly and then gradually stabilizes, but the temperature in the stable interval is higher, which can cause injury to personnel. The distance between the two fire sources had a great influence on the temperature distribution between the fire sources. As the distance between the fire sources increased, the stable temperature in the area between the two fire sources gradually decreased, and therefore, the impact on the evacuation of people gradually decreased. The temperature distribution law between dual fire sources can provide a reference for the rescue of people trapped in the initial stages of a fire.