主管：中华人民共和国应急管理部
主办：应急管理部天津消防研究所
ISSN 1009-0029  CN 12-1311/TU
Fire Science and Technology

Fire Science and Technology ›› 2024, Vol. 43 ›› Issue (9): 1328-1334.

Previous Articles    

Research on optimizing liquid nitrogen fire extinguishing efficiency in urban underground logistics systems through enhanced

Ning Zhaoyu ,Yuan Diping, Zhang Guowei, Xu Dunbin   

  1. Fire suppression systems commonly used in narrow and confined spaces have limitations when applied in urban underground logistics systems, making them difficult to implement directly. To investigate the improvement in liquid nitrogen extinguishing efficiency under the influence of enhanced longitudinal ventilation in urban underground logistics systems, this study analyzes the changes in oxygen volume fraction and ceiling temperature under different working conditions by varying wind speed and nitrogen injection position. The results indicate that nitrogen injection can effectively extinguish fires in underground logistics tunnels, and enhanced longitudinal ventilation significantly improves the extinguishing efficiency of liquid nitrogen. When the nitrogen injection distance is 50 m, the extinguishing efficiency under a wind speed condition of 2 m/s is increased by 41.86% compared to a wind speed condition of 0 m/s. Additionally, at a fixed nitrogen injection distance, enhanced longitudinal ventilation significantly advances the time when the temperature and oxygen volume fraction near the fire source begin to decline. Moreover, as the nitrogen injection distance increases, the time for the temperature and oxygen volume fraction near the fire source to decline is delayed; however, enhanced longitudinal ventilation can mitigate the lag in cooling and asphyxiation effects caused by the increased injection distance. These findings provide important theoretical support for fire suppression research in urban underground logistics systems.
  • Accepted:2024-09-15 Published:2024-09-23
  • Contact: 江苏省自然科学基金面上资助项目（BK20221548）；深圳市科创委2022年度基础研究专项面上项目（JCYJ20220530164601004）

Abstract: underground fire; urban underground logistics systems; liquid nitrogen extinguishing; enhanced longitudinal ventilation