隧道内贴壁火顶棚射流温度及火焰特性研究

Study on temperature and flame characteristics of ceiling jet induced by wall-attached fire in a tunnel

为探究隧道内贴壁受限火羽流驱动的顶棚射流特性,开展隧道火灾试验,选取4种长宽比的矩形火源,分析3种燃烧器上表面与隧道顶棚的距离和4组火源功率对顶棚下方火焰蔓延及温度分布的影响特征。结果表明:随着火源功率增大、燃烧器上表面与隧道顶棚距离的减小,隧道顶棚横向和纵向温度升高;燃烧器长宽比增加,顶棚射流横向火焰的蔓延长度及横向温度也增大,而纵向火焰长度减小;不同长宽比对应的纵向火焰长度差值随火源功率增加而增大,最大值为0.36 m。

In order to study the ceiling jet characteristics induced by the wall-attached fire in a tunnel,tunnel fire experiments were conducted.Four rectangular fire sources with different aspect ratios were selected,and the influence of three source-ceiling distances and four heat release rates on flame spread and temperature distribution under celling were analyzed.The research found that with the increase in heat release rates and decrease of the source-ceiling distance,the temperature of the tunnel ceiling increases in both transverse and longitudinal directions.As the aspect ratio of the burner increases,the spread length and transverse temperature of ceiling jet transverse flame also increase,while the longitudinal flame length decreases.Meantime,the longitudinal flame length difference of different aspect ratios increases with the heat release rates,and the maximum value is 0.36 m.