综合管廊电缆舱灭火系统效果研究

针对某综合管廊的电缆舱室，采取全尺寸实验和数值模拟结合的方法，探究综合管廊内电缆舱的火灾特性，对比分析干粉灭火系统和高压细水雾灭火两种灭火系统的灭火效果。将火源功率为0.7 MW 的乙醇火设置于电缆架底部，观察火灾发展和烟气蔓延情况，分析电缆舱火灾特性；对比两种灭火系统开启后管廊内的温度和烟气变化规律，分析灭火效果。在实验基础上利用FDS 软件进行数值模拟以补充验证多工况火灾灭火结果。结果表明，电缆舱关闭防火门后，火灾不会持续发展，舱内温度稳定在600～700 ℃之间；干粉灭火系统有效灭火时间较短，且降温效果有限，火源上方温度降至440 ℃后发生了复燃现象；高压细水雾系统有效灭火时间较长，可以持续进行灭火，降温效果较为明显，且对于烟气蔓延有较明显的抑制作用，能为后续消防队员进入创造有利条件。

Study on the effect of fire extinguishing system in cable compartment of utility tunnel

In order to investigate the characteristics of cable fire and analyze the fire suppression effect of powder extinguishing system and high- pressure water mist system, a series of fullscale experiments and numerical simulations were conducted in the cable compartment of a practical utility tunnel project. A ethanol fire with HRR=0.7 MW was set under the bottom cable rack. The corresponding development of fire and the spread of smoke were observed to analyze the characteristics of cable fire in the cable compartment. By comparing the changes in temperature and smoke under two common-used fire suppression systems, the suppression effect of powder and high-pressure water mist systems were analyzed. Based on the full- scale experiments, the simulation software FDS was adopted to supplement and verify the results. Results indicate that after closing fire door of cable cabin, cable fire could not keep spreading, and the temperature stabilized between 600 ℃ and 700 ℃ . The powder extinguishing system had a quite short effective extinguishing time and a limited cooling effect. When the temperature above the fire source dropped to about 440 ℃ , cables began to reignite. By contrast, the water mist system could suppress fire for a consecutive and longer time and had a markedly positive influence on reducing temperature and suppressing the spread of smoke. Therefore, the water mist system could bring beneficial conditions for firefighters to enter the compartment and rescue.