综合管廊电缆火灾窒息灭火试验与数值模拟研究*

为研究综合管廊电缆火灾窒息灭火有效性，采用缩尺寸试验与数值模拟方式，研究不同线缆数量、线缆布置间距、线缆分层情况对窒息灭火时间的影响，以及火灾过程中线缆热释放速率、烟气高度、环境温度、CO体积浓度、O2体积浓度等关键参数的变化，判定最佳防火门关闭时间与电缆火灾窒息灭火时间。研究结果表明:在密闭情况下，线缆数量越多，综合管廊电缆火灾窒息时间越短；对于相同线缆数量，在线缆按一定间距布置情况下，窒息时间更短；对于双层线缆布置，线缆按一定间距布置情况下的窒息时间反而更长；防火门关闭时间t关为350 s时，可满足人员安全疏散需求；采用窒息灭火方式时，电缆火灾灭火时间t灭约为1 620 s。研究结果可为地下管廊电缆灭火提供试验方法参考和数据支持。

Experimental and simulation study on cable fire extinguishing by smothering in utility tunnel

In order to study the effectiveness of cable fireextinguishing by smotheringin the utility tunnel,the influence of different cable quantities,cable arrangementspacing and cable layering on thetimeof fire extinguishingby smothering,as well as the change of cable heat release rate,smoke layer height,ambient temperature,CO concentration,O2 concentration and other key parameters in the process of fire were studied by using the reduced-scale test bench and numerical simulation method,and the closing time of fire door and the time of cable fire extinguishingby smothering were further determined.The results showed that the larger thecable quantity,the shorter the smothering time under closed conditions.For the same cable quantity,the smothering time was shorter when the cables were arranged according to certain spacing.For the double-layer cable arrangement,the smothering timewas longer when the cables were arranged according to certain spacing.When the closing time of fire door was 350 s,it could meet the need for the safe evacuation of personnel.The time of cable fire extinguishing by smotheringwas 1 620 s.The research conclusion can provide some reference of test methods and data support for the cable fire extinguishing in underground pipe gallery.