Study On Air Age And Smoke-Control Of Fire At Subway Central-Platform

Ventilation system is a key component of subway station, also study on smoke-control of fire is of much importance for subway safety. During subway travel, so many passengers wait train at and pass by station platform, so concern for good air quality in normal state and safety out of fire at platform is always challenging and difficult.Based on ventilation measurement and fire experiment at stations of Tianjin Subway Line 1, this paper checks affecters of air age, and establishes reasonable ventilation strategies to decrease air age at central-platform. As to fire at station central-platform, this paper works much on theory of smoke-control, including minimal longitudinal ventilation velocity, image analysis to flame of experimental fire, wave motion of smoke, energy transformation in fire, etc. Those results mainly come out with the following:Air flow motion theory is built to analyze motion time of ventilation air flow, find out affecters of air age, then reasonable strategies are used to optimize air flow distribution, decrease air age and obtain better air quality at subway station platform. Analysis to experimental fire images at subway station platform identifies special fire developing process, other than the conventional fire types, and serves to guidelines for calculation of temperature and velocity in FDS etc.When smoke pressure changes with mass of certain power, a kind of linear wave equation for smoke can be derived from the conservation equations. These results make progress in theoretical explanation, propagation equation and simulated reconstruction of smoke wave, and also put forward some new ideas for smoke-control in subway fire environment.Longitudinal ventilation can be activated in subway station platform fire, to stratify temperature, mass rate of smoke and air quality upstream fire source, creating a zone free from smoke for evacuee and fire-fighters, with effective cost and energy.Observe fire and smoke-control strategies in view of energy conversion, select smoke-control mode, further determine whether the energy consumption during subway fire can be reduced, all of which guarantee safety for evacuation, clear room for fire-fighting, and protect environment of subway station platform.