火焰撞击受限顶棚条件下顶棚最高温度数值模拟研究

顶棚下方最高温度是隧道火灾发展蔓延时的重要参数。针对火焰撞击顶棚并受到顶棚侧墙限制的强羽流驱动的顶棚射流,利用FDS模拟了18种缩尺寸隧道火灾工况,研究了顶棚下方最高温度随着火源功率、火源与顶棚距离的变化规律。结果表明:火焰撞击区域附近顶棚下方温度随着火源功率的增大而降低,随火源与顶棚距离的增大而升高;相反,在远离火源区域顶棚下方的温度随火源功率增大而升高,随火源与顶棚距离增大而降低;同时,通过分析隧道中心面上顶棚下方温度分布规律,提出了火焰撞击受限顶棚时顶棚下方最高温升的预测模型,研究结果能为实际的隧道消防提供一些参考。

Numerical simulation of the maximum temperature beneath ceiling for an impinging flame beneath a confined ceiling

The maximum temperature beneath the ceiling is an important parameter for the development of tunnel fires. This paper investigates the maximum temperature beneath ceiling for an impinging flame beneath the confined ceiling in a channel. 18 fire conditions with various heat release rates and source-ceiling heights are simulated by FDS (Fire Dynamics Simulator). The results show that the temperature beneath the ceiling increases with the heat release rate and decreases with the source-ceiling height in the zone near the flame impingement, however, it decreases with the heat release rate and increases with the source-ceiling height in the zone away from the fire source. Besides, the maximum temperature rise beneath the ceiling in each scenario is analyzed and then an empirical correlation for the maximum temperature beneath the ceiling was proposed based on the fitting of the data. This study is expected to provide some references for actual tunnel firefighting.