综合管廊电缆火灾细水雾灭火性能研究

Study on Water Mist Fire Extinguishing Performance for Cable Fire in Utility Tunnels

以城市地下综合管廊内的电缆舱作为研究对象,考虑环境、工况的特殊性,提出将细水雾灭火系统应用于电缆火灾防控,并设计参数优化方案。利用火灾动力学模拟工具FDS,建立全尺寸综合管廊电缆舱数值模拟模型,设置合理的网格划分方案和电缆参数,对10 MPa、14 MPa、17 MPa、20 MPa喷头压力下细水雾灭火系统的灭火效率和效果进行讨论。研究发现:1)适当增加细水雾灭火系统的喷头压力,有利于提高细水雾的灭火效率。2)当喷头压力为20 MPa时灭火时间最短,当喷头压力为14 MPa时热释放速率(HRR)下降幅度最大,但这两个喷头压力下数值波动范围较大,可能削弱对烟气的洗涤作用。3)当喷头压力为17 MPa时,在火焰发展和熄灭阶段,近火端温度均相对较低。综合多方面因素,当细水雾灭火系统喷头压力为17 MPa时,综合管廊电缆火灾防控效果最好。

Taking the cable cabin in the urban underground utility tunnels as the research object,considering the particularity of environment and working conditions,the application of water mist fire extinguishing system in the cable fire prevention and control is put forward,and the parameter optimization scheme is designed.The fire dynamics simulation tool FDS is used to establish a full-size utility tunnel cable cabin numerical simulation model,and reasonable grid division scheme and cable parameters are set.The fire extinguishing efficiency and effect of the water mist fire extinguishing system under the nozzle pressures of 10 MPa,14 MPa,17 MPa and 20 MPa are discussed.It is found that:1)Increasing the nozzle pressure of water mist fire extinguishing system appropriately is beneficial to improve the fire extinguishing efficiency of water mist.2)When the nozzle pressure is 20 MPa,the extinguishing time is the shortest,and when the nozzle pressure is 14 MPa,the Heat Release Rate(HRR)decreases the most.However,the numerical fluctuation range under these two nozzle pressures is large,which may weaken the washing effect on flue gas.3)When the nozzle pressure is 17 MPa,the temperature near the fire end is relatively low in the flame development and extinguishing stages.According to these various factors,when the nozzle pressure of water mist fire extinguishing system is 17 MPa,the cable fire prevention and control effect in utility tunnels is the best.