Research On Fire Ventilation Of Highway Tunnel Based On FDS

Fire is one of the biggest threats to the safe operation of highway tunnels,the fire not only damages the tunnel structure,but also threatens people's lives and property.In recent years,domestic and international tunnel fire accidents are painful lessons.Ventilation control,as one of the key part of tunnel fire rescue,directly affects the development trend and harmful consequences of fires.Based on the Qinling No.1 Tunnel uplink,this thesis will study the fire ventilation of longitudinal ventilation tunnel with single ventilation shaft.In this thesis,using the numerical simulation technology of computational fluid dynamics,a local tunnel model is established by using FDS software in Qinling No.1 Tunnel uplink to simulate a fire with a maximum Heat Release Rate of 30 MW.Combined with the effect of different longitudinal winds in the tunnel on the fire as well as the common unfavorable conditions in the tunnel fire ventilation,five kinds of working conditions are designed for simulation and analysis,Including: Simulating tunnel fires under different longitudinal wind conditions,observing the law of flue gas diffusion,so as to get critical wind speed of fire;Simulating the tunnel fire in the condition of no longitudinal wind,small longitudinal wind,critical wind speed,obtaining the variation law of temperature field and smoke field in tunnel,so as to make out its effect on evacuation,tunnel structure and fire rescue;Under the smoke exhausting mode of the ventilating shaft,simulating the ventilation and smoke exhaust of the exhaust duct under different wind speed conditions,observing the smoke exhaust effect of the exhaust duct,hence,the suggested wind speed value of exhaust duct is given.When a fire occurs in the tunnel,it is usually met with the unfavorable conditions of difficult to distinguish the fire scale,delayed opening of the jet fan and disturbance of the natural wind.The above unfavorable conditions are simulated respectively in the design conditions.Through the analysis of the simulation results,the effects of the above unfavorable conditions on the evacuation of personnel,tunnel structure and fire rescue are obtained.Combined with the above research results,the fire rescue was divided into the safe evacuation phase and the fire-fighting rescue phase,considering the effects of natural ventilation power,traffic ventilation power,fume resistance and fan on fire ventilation,through analysis,the control strategy of fan in each phase of Qinling No.1 Tunnel uplink was make out,which can also provide reference for fire ventilation in the same type of tunnel.