在高速铁路长大隧道中，列车车厢内部着火后，车窗玻璃可能被击碎或受热变形，并破裂脱落形成新的通风口，产生由该通风口向隧道内蔓延的开口火溢流，从而扩大火灾规模，造成更大灾害。文中对该类开口火溢流的卷吸行为及燃烧特性进行了研究，揭示了车厢内部烟气温度的纵向衰减规律；利用能量平衡方程及自然对流换热和辐射换热公式，提出了车厢内、外火灾热释放速率的计算方法；建立了开口火溢流角度与火源功率及特征长度之间的耦合关系式；得到了隧道壁面处最大无量纲温度与无量纲溢出火源功率之间的关系模型。结果表明，车厢内、外的热释放速率随火源总释放速率的增加均呈抛物线规律增加，当总的火源热释放速率为17.85MW时，车厢内、外的热释放速率相等；火源热释放速率在1~15MW范围内时，车厢内释放速率均大于溢出车厢外的释放速率；火源热释放速率在20~30MW范围内时，车厢内释放速率均小于溢出车厢外的释放速率；随着火源释放速率的增加，溢出的热烟气增多，隧道壁面处的温度升高，且在3m左右的高度达到最大值；热释放速度大于20MW时，直接有火焰溢出。

When the passenger compartment caught fire in the long high-speed railway tunnel, the window glasses may be deformed and break off to form new vents, which can accelerate the fire combustion. The flame will eject to tunnel from the opening and lead to catastrophic loss of casualties and properties. This paper studied the behavior characteristics of the ejected flame and the longitudinal distribution law of smoke temperature in the high-speed train compartment. Based on the energy balance equation, methods for calculating the heat release rate (HRR) in and out of the on-fire train were put forward, and the coupling relationship between the flame tilted angle and HRR was established. Moreover, the coupling relationship between the maximum dimensionless temperature near the tunnel wall and the dimensionless flame ejecting HRR was obtained. The results show that the HRR in and out of the on-fire train compartment increases in the parabolic rule. The HRR in and out of the on-fire train compartment are equal when the whole HRR is 17.85MW; the HRR in the on-fire train compartment is larger than that flame ejecting HRR when the total HRR is within the range of 1MW to 15MW. But HRR in the on-fire train compartment is smaller than that out of the on-fire train compartment when the total HRR is within the range of 20MW to 30MW. With the increase of the total HRR and hot-gas, the temperature near the tunnel wall increased, and the highest temperature appears in position of 3 meters high. The flame will eject when the HRR is above 20MW.