Ventilation Strategies Of Smoke Spread In T-intersecting Tunnels,Y-intersecting Tunnels And Sloping Tunnels

With the increasing number of tunnels and tunnel length in China,all kinds of tunnel fire accidents have occurred frequently,resulting in heavy casualties and major economic losses.Poisonous smoke with high temperature caused by the fire is the main cause of personal injury.At present,the current commonly used method of fireproofing and smoke exhaust is vertical,which means to prevent the spread of fume upstream by controlling the critical wind speed,and extract the fume downstream from the tunnel outlet or smoke exhaust silo.Besides,it is too general to use the same control strategy in one smoke zone,ignoring the specific location of fire.Therefore,on the basis of a large number of previous studies,the author analyzes the tunnel fire environment by dividing the fire into different stages of development to provide guidance for the evacuation of personnel escape.In this paper,the research status of highway tunnel fire at home and abroad is reviewed first,and then the CFD(Computational Fluid Dynamics)is used to analyze the fire environment of highway tunnels.After that,the influence of different complex geometrical structures on the natural development of tunnel fire is studied,which provides a guiding significance for personnel evacuation at the beginning of the fire.At last,the author analyzes an actual project of a highway tunnel,where the FDS software is used to simulate the natural spread of the smoke and the distribution of velocity field,temperature field,visibility field in different places of the tunnel under different ventilation control strategies.The main work of the paper is as follows:1.Simulate the effects of various geometric characteristics of highway tunnels on the natural spread of tunnel fires and on the entire fire environment.This paper mainly simulates the influence of T-intersecting tunnels,Y-intersecting tunnels and sloping tunnels on the natural development of the tunnel fire.2.Taking an actual highway tunnel project as an example,the FDS software is used to simulate,when the fire breaks out in different places of the tunnel,the effects of tunnel smoke control and the distribution rules of velocity field,temperature field and visibility field under the existing ventilation and smoke control strategies,which can provide great guidance for personnel evacuation.