The Smoke-control Research Of Urban Underground Fast Road Under A Fire

As a new way of tunnel transportation,the Urban Underground Fast Road can play an important role in terms of easing traffic pressure on the ground-As a result,a number of large cities with dense population and serious traffic problems have already begun planning or even constructing this kind of road.Because of the seal of the underground space,serious property damage and casualties will be suffered in the event of a fire.Therefore the research of smoke-control and personnel-evacuation safety in a tunnel fire have received more and more attention of domestic and foreign research and design personnel.In order to obtain statistics of state parameters such as smoke,temperature and velocity in the tunnel,as well as their distribution of space and time after a fire break out,two kinds of methods was adopted:one is the smoke-control experiment of an actual-sized tunnel and the other is the numerical simulation using CFX,which is a kind of large-scale fluid analysis software. As a consequence,the longitudinal,transverse and vertical spatial distribution of smoke and temperature in the process of combustion are obtained and also how the average velocity of a specific cross section changes with time under different conditions. After detailed generalization and summarization,the motion path of smoke in the entire tunnel and the fans’influence on smoke distribution and longitudinal velocity are acquired,which provide basis for the design of fire alarm system,the ventilation system,the smoke exhaust system and the escape and rescue plan.On the other side,by means of comparison between experimental and simulative results, it is verified that the result of simulation deserves considerable reference, but its limitation cannot be ignored.