分岔隧道强羽流驱动的顶棚射流火焰特征

为探究分岔隧道强羽流驱动的顶棚射流横向长度、纵向长度及火焰面积分布特征,选取火源中线距侧壁0.1、0.3、0.5、0.7和0.9 m等5个火源位置,47.9、63.8、77.7和95.7 k W等4个热释放速率(HRR),分析和确定典型工况下间歇性火焰和连续火焰的横向长度和临界温度,临界温度值分别为325和620℃;以连续火焰的临界值为依据,进一步得到顶棚射流连续火焰的横向长度、纵向长度及火焰面积。结果表明:随着火源中线与侧壁间距从0.1~0.7 m变化,横向火焰长度呈现非单调的趋势,且当间距为0.3 m时,横向火焰长度最大;纵向火焰长度随火源中线与侧壁间距从0.1~0.9 m增加而逐渐减小,且相同工况下纵向火焰长度均长于横向火焰长度;火源中线与侧壁间距从0.1~0.3 m增加,火焰面积逐渐增大,当间距增加至0.7 m,火焰面积逐渐降低。

Flame characteristics of ceiling jet flow driven by strong plume in bifurcation tunnels

In order to explore transverse and longitudinal length and flame area distribution features of ceiling jet flow driven by strong plume in a bifurcation tunnel,5 groups of fire locations(0.1,0.3,0.5,0.7 and 0.9 m)and 4 HRR(47.9,63.8,77.7 and 95.7 k W)were selected.Transverse lengths of intermittent flame and transverse continuous flame for typical working conditions were calculated and corresponding critical temperature values were determined,which were 325 and 620℃respectively.Based on critical values of continuous flame,its transverse and longitudinal flame length as well as flame area were obtained.The results show that there is a non-monotonic trend for transverse flame length as distance from fire source to sidewall increases from 0.1 m to 0.7 m,and it will reach maximum value at 0.3 m.Nevertheless,longitudinal length continuously decreases as distance rises from 0.1 m to 0.9 m,and it is always larger than transverse length under same conditions.Flame area increases first with spacing grows from 0.1 m to 0.3 m and then decreases as it continuously increases to 0.7 m.