隧道火灾纵向通风下羽流触顶区温度变化研究

On temperature change of tunnel top plume in a longitudinal ventilation

根据Boussinesq相似性,利用流体力学基本方程,建立隧道火灾羽流三维模型,并借助量纲分析方法,推导了触顶区温升公式。在假设的隧道模型下,通过改变火源功率和纵向风速设计了多个算例,利用温升公式进行计算,并与场模拟结果比较,归纳了触顶区温度的变化规律。结果表明,同一火源功率下,触顶区温度随纵向风速增加而降低,并趋于一稳定值,其大小约为最高温度的1/3。还对温降过程中的突变现象进行了分析,讨论了中心低温区及不同羽流对温度的影响。最后对火灾救援的通风策略提出了建议。

This paper aims to report the authors＇ study on the temperature change of the plume on the tunnel top in a longitudinal ventilation. The whole study is done on the Boussinesq approximation and equation of fluent mechanics in hoping to develop a 3 dimensional model of plume. As a result, a formula on calculating the tunnel top temperature has been worked out. At the same time, different fire source strengths and the wind speeds are then built in the given tunnels. When the comparison of the calculation results was analyzed, the regularity of temperature varieties could be concluded. The results show that the temperature of plume on the tunnel top deduced with the increase of the airflow speed and a certain value tend to be equal to 1/3 maximum temperature approximately. The present paper has also discussed the influence of different plumes on the temperature of the center area. Finally, some suggestions have been advanced for controlling the ventilation in the tunnel fire.