管廊内电缆内热源燃烧过程数值模拟研究

Numerical simulation research on combustion process of heat sources inside cables in pipe gallery

为预防综合管廊局部空间内部电缆火灾事故的发生,运用火灾动力学模拟软件(FDS)三维传热和热解模型,对15 kV铜芯电缆着火过程建模分析,分析不同条件下电缆温度分布、热解气体分布以及热释放速率(HRR)曲线,以及热源功率大小和持续时间对电缆燃烧过程的影响。结果表明:随着热源功率的增加,电缆着火时间缩短,火灾危险性增加;HRR峰值和最大火蔓延长度(FSL)随着热源功率的增加呈线性增长;及时阻断热源功率可有效预防火灾的发生;热源功率消失后的火焰残留时间随着热源功率持续时间的增加整体呈现先上升后下降的趋势。

In order to study the combustion process of the cable in the local space of the unity tunnel under an internal heat source,the ignition process of the 15 kV copper core cable was analyzed by using the 3D heat transfer and pyrolysis model of fire dynamics simulator(FDS).By analyzing the cable temperature distribution,pyrolysis gas distribution and heat release rate(HRR)curve under different conditions,the influence of the power and duration of the heat source on the cable combustion process was studied in detail.The results show that with the increase of heat source power,the cable ignition time is shortened,and the fire risk increases.The peak HRR and maximum fire spread length(FSL)increase linearly with the increase of heat source power.Blocking the heat source power in time can effectively prevent the occurrence of fire.The flame remaining time shows a trend of rising first and then falling as the duration of the heat source power increases.