Research on Temperature Distribution of Cable Fire in Utility Tunnel and Fire Extinguishing Efficiency of High-Pressure Water Mist Fire Extinguishing System

Utility tunnel plays a critical role in concentrating various important urban engineering pipelines but faces severe fire risks and safety threats. In this study, the temperature distribution characteristics of cable fire in utility tunnel were studied by means of full-scale fire experiment, and the effects of spray intensity, cable fullness and ambient wind speed on fire extinguishing efficiency of high-pressure water mist fire extinguishing system (HWMFES) were investigated. The results show that the maximum heating area of cable fire in utility tunnel is localized to the three cable bridges nearest to and directly above the fire source, with a highest temperature exceeding 800°C, while other areas on the same side and the opposite side are negligibly affected. Increasing spray intensity significantly enhances the fire extinguishing efficiency of HWMFES. Reducing cable fullness can effectively shortens the fire extinguishing time of HWMFES. providing longitudinal ventilation of 2 m/s in utility tunnel can significantly improve the fire extinguishing efficiency of HWMFES. The results of this research can provide a theoretical foundation and data support for the engineering application of HWMFES in utility tunnels.