Simulation Of Smoke Isolation Passageway System For Side Air Supply In Underground Tunnel Fire

In recent years,tunnels have made tremendous contributions to national economic,political,cultural and ecological construction.Tunnel construction technology in China has reached the world's high level.Tunnel construction technology involves multi-disciplinary and multi-professional intersection.With the increasing number of tunnels designed and the length of tunnels in China,tunnel fire accidents often occur.After the tunnel fire,the visibility of the tunnel decreases,and it is difficult for people to escape.In a short time,it causes serious irreparable losses to people's lives and property.Therefore,on the basis of previous studies,the author focuses on the design of ventilation and smoke isolation scheme for tunnel escape,studies the fire environment in the tunnel,and chooses a reasonable smoke isolation scheme to provide basis and reference for fire rescue and personnel escape.In this paper,Pyrosim fire simulation software is used for numerical simulation.A horizontal and vertical combination of breathing zone collision air tunnel fire evacuation system(HVES),A upper and lower combination of breathing zone collision air tunnel fire evacuation system(ULES),and A top oblique blown breathing zone air supply tunnel fire evacuation system(TOES)are introduced.The visibility field,CO concentration field and temperature field in tunnel fire are simulated and analyzed.The main work and conclusions of this paper are as follows:(1)The ventilation effects of HVES tunnel escape system and five traditional tunnel ventilation systems in tunnel fire are simulated,and the visibility field,CO concentration field and temperature field of six ventilation systems in tunnel fire are compared;HVES can create a very obvious smokeless side escape passage,and HVES is more conducive to evacuation than the traditional system.(2)For HVES system,considering both air supply and smoke control effect,the first nozzle V1 = 0.8 m/s and the second nozzle air speed 0.2 m/s have achieved good results.(3)Compared with the traditional five ventilation systems,when using ULES system,it can create a smoke-free edge,CO concentration is approximately 0 ppm,and the temperature is relatively low.(4)When the wind speed ratio of the two nozzles in ULES system is V1 = 0.7 m/s,V2 = 0.3 m/s,V1 = 0.8 m/s,V2 = 0.2 m/s or V1= 0.9 m/s,V2 = 0.1 m/s,the overall visibility of the escape zone at the edge of the tunnel is maintained at 30 m,the CO concentration is close to 0 ppm,and the temperature field is below 40?(5)When the TOES system is used,a relatively smokeless and clean passage can be created at the edge;when the angle of air supply is 90°,the flue gas at the edge of the tunnel can be well controlled,and the visibility is 30 m,the CO concentration is 10 ppm,and the overall temperature is below 40?.The research of this topic provides theoretical reference for the study of fire related topics in tunnels,and also provides a basis for the design of evacuation and smoke control and exhaust in tunnels.