Fire Flashover Control By High Pressure Water Mist And Longitudinal Ventilation In Highway Tunnel

With the rapid urbanization process,increasing traffic road tunnels,security issues have also been followed by all parties concerned.Analysis of Highway Tunnel ventilation exhaust from effectively controlled fire development and smoke spread for evacuation for sufficient time to create the most favorable environment has become an important issue to escape study.Water mist fire extinguishing systems are environmentally friendly,efficient,water-saving and good electrical insulation and other advantages,but the effect will depress mist fumes,smoke layer thickness increases.The author analyzes the road tunnel longitudinal ventilation jet and high pressure water mist under Highway Tunnel Fire smoke and fire control were studied.Firstly,the use of FDS software to build 20MW 1000m long road tunnel fire model,the arrangement within the road tunnel jet fans simulation analysis,the lateral spacing of the jet fan 0m,2m,4m simulate longitudinal spacing of 50m,100m,150m,200m,250m simulate tunnel ventilation comparison of smoke layer height,visibility,CO and other parameters of the analysis showed that the lateral spacing of the model under conditions of jet fans 2m,smoke effect is better when the longitudinal spacing 200m.Secondly,this paper analyzes the longitudinal ventilation control of road tunnel fire smoke through longitudinal ventilation velocity of 1.8m/s,2.1m/s,2.4m/s,2.7m/s simulation analysis,through a tunnel fire smoke changes changes,the tunnel gas concentration,temperature and other parameters of the fire found that under the conditions of the model,when the wind speed reaches longitudinal ventilation 2.7m/s,the ability to take complete control of the tunnel of smoke in the fire the wind,the wind to provide a favorable range escape.Finally,the author focuses on the role of water mist fire flashover road tunnel control,water mist nozzles are arranged in the upper area of the fire,by simulating the discovery,rational layout,open mist smoke layer temperature can be controlled at flashover critical temperature occurs about,effectively inhibit flashover;analyze the impact of different application time of water mist fire flashover,duration of action of different water mist fire flashover affect the results will have a big difference,at the beginning of the fire applying a water mist fire control better,when applied near the crashing water mist does not only inhibit flashover occurs,but may exacerbate conduct flashover.