Study On Fire Smoke Control Of Urban Long And Wide Underwater Tunnel

The urban long and wide underwater tunnel has its special features in terms of function positioning and geographical location,and has the characteristics of limited construction conditions and complicated structure.Once a fire occurs in the tunnel,if the smoke cannot be exhausted in time,it will cause serious life safety for people Threats,in this paper,the urban long-width underwater highway tunnel centralized smoke exhaust system research,to explore the appropriate urban long-width underwater tunnel fire exhaust system,for the future design,construction and change Provide reference for further research.The main research work of this article is as follows:According to the characteristics of the length of the underground buried section of the tunnel and the width of the lateral dimension,a mathematical and physical model of the tunnel is established.Consult relevant literature to determine fire smoke control indicators.Through theoretical calculation and combining the tunnel structure,geographic location,traffic conditions and surrounding environment,the parameters such as simulation time,fire scale,and fire development rate are determined.According to the characteristics of the tunnel structure and the different locations of the fire sources,the fire smoke extraction plan is analyzed.Use FDS simulation software to study the smoke exhaust effect of three different centralized smoke exhaust modes,analyze the distribution of speed field,temperature field,visibility field,and CO concentration in the tunnel under different fire scenarios,compare the fire smoke control indicators,and explore The most reasonable smoke extraction program.The results show that the three smoke exhaust modes can meet the smoke control index,and the double side centralized smoke exhaust mode has the best smoke exhaust effect.Analyze the flue gas flow characteristics in the tunnel under the two-sided centralized smoke exhaust mode,and study the smoke distribution law above different lanes to determine the most unfavorable lanes for fire smoke control.The effects of different smoke volume,longitudinal wind speed,and smoke vent parameters on the smoke exhaust effect of the fire were studied.On the premise of meeting the smoke control index,the influence of smoke on the evacuation of personnel and energy saving were considered,and the most explored Reasonable smoke exhaust plan.The results show that the most reasonable smoke extraction scheme in the tunnel using the"concentrated lateral smoke extraction+longitudinal wind"mode is the smoke emission volume of 200m~3/s,the longitudinal wind speed of 1.5m/s,the number of smoke exhaust ports,and the area of smoke exhaust ports.6m~2,the smoke exhaust port spacing is 70m,and the smoke exhaust port opening method is 2 upstream and 4 downstream.To study the smoke control strategy when the fire source is located on the slope section,by analyzing the smoke spreading characteristics in the tunnel under different smoke exhaust amount,longitudinal wind speed,and smoke vent opening method,it is proposed to increase the smoke exhaust volume and reduce the wind speed 1.Measures to change the way the smoke vents are opened to optimize the smoke control plan.