基于移动火源的隧道拱顶温度分布规律实验研究

为掌握行进中的着火机动车对隧道拱顶温度场分布的影响规律，以公路隧道为原型建立了1∶20小尺寸实验系统，在隧道自然通风条件下，模拟了移动火源以0.5，0.8和1.0 m/s等不同速度在隧道中行进、停止直至熄灭的火灾过程。研究了移动火源进入隧道后的隧道温度场及火灾过程中隧道拱顶沿纵向温度分布特征、测点温度峰值及梯度变化等规律。研究结果表明：① 当火源行进速度为0.5 m/s时，燃烧更加充分，隧道拱顶温度达到峰值，比其余两组高40和50 ℃；② 移动火源的存在，打破了顶棚射流拱顶热烟气与下部冷空气的对流循环动态平衡，减弱了热对流效应，使得隧道内温度降低更缓慢。

Experimental study on longitudinal temperature distribution law of tunnel ceiling based on moving fire source

In order to reveal the influential law of mobile fire vehicle on the temperature distribution of tunnel ceiling，the 1∶20 physical model was designed according to real road tunnel.Under natural ventilation condition，the fire process when mobile fire source with velocity of 0.5，0.8 and 1.0 m/s moved into tunnel then stopped till burned out were studied.The temperature fields when fire source moved into tunnel were studied.The ceiling temperature distribution and temperature peak in fire process and its gradient were analyzed.The research results indicate that：① Fire source of 0.5 m/s combusts much more adequately than the other two，which leads the temperature peak of tunnel ceiling 40 and 50 ℃ higher than that of 0.8 m/s and 1.0 m/s fire source；② The existence of moving fire breaks the balance of convective circulation of hot smoke and fresh cold air caused by jet effect，which weakens thermal convection and slows the temperature decrease in tunnel.