纵向风和阻塞比对隧道双火源温度分布的影响

Influence of longitudinal ventilation and blockage ratio on temperature distribution in tunnel with double fire sources

为研究城市公路隧道内纵向通风和障碍物对双火羽流行为的影响,采用数值模拟方法分析双火羽流纵向烟气温度变化规律。研究结果表明:随着风速的增加,顶棚下方最高温度不断降低,烟气逆流现象逐渐减弱至消失;随着阻塞比的增加,下游火源一直向下游倾斜,而上游火源逐渐由向下游倾斜转变为向上游倾斜;基于流体力学理论,引入阻塞比修正无障碍物时的弗劳德数,进而建立适用于隧道内有障碍物的双火羽流顶棚最高温升分段预测模型,研究结果可为隧道火灾防治提供基础数据和理论参考。

In order to study the influence of longitudinal ventilation and obstacles on the behavior of double fire plumes in urban road tunnel,the numerical simulation method was used to analyze the change of longitudinal smoke temperature with double fire plumes.The results showed that as the wind velocity increased,the maximum temperature under ceiling decreased,and the phenomenon of smoke backflow gradually weakened to disappear.As the blockage ratio increased,the downstream fire source always inclined to downstream,while the inclination of upstream fire source gradually changed from downstream to upstream.Based on the theory of fluid mechanics,the blocking ratio was introduced to modify the Froude number without obstacles,then a piecewise prediction model for the maximum ceiling temperature rise of double fire plumes with obstacles in tunnel was established.The research results can provide basic data and theoretical reference for the prevention and control of tunnel fire.