Natural Ventilation And Fire Research Of Underground Double Island Type Station

With the rapid development of social constructions,land resources become increasingly tight. The types of tranditional ground transportation has been limited,but recently the appearance of new underground station alleviate extremely the limitation,so the traffic become more convenient and efficient.However,the energy consumption is very huge for the environmental control system of underground station.so it becomes very concerned issue to decrease the energy consumption of the environmental control system in designing control system.To decrease the energy consumption,it is a feasible ventilation technology measure to use the piston wind aroused by movement of a train to decrease temperature,through opening ventilation holes on top of running tunnel and station tunnel.Firstly,the paper simulated and analysed the distribution of temperature above station platform about three different states when a train was running into station through establishing MeiLan airport underground station,.and compared the average temperature above station platform with thermal comfort index established in advance.The results show that the temperature didn’t meet the comfort requirements.The paper simulated the fire characteristics of this station model,and the results show that indexes of the temperature and CO density at1.8m plane above the platform were all in security value.Secondly,the paper simulated and analysed how the barrier door influenced thermal environment and fire smoke distribution.The results show that the station’s thermal environment didn’t meet the comfort index,but the results of fire meet the requirements people need to withdraw.Although the barrier door can prevent the fire smoke from entering the platform area,it weakened the influence,the piston impacting on platform,and stopped heat producing by people from exhausting platform.Moreover,the paper analysed how the train number and location of stopping impacted on the temperature distribution,and introduced concept of thermal driving and elaborated how it influenced the air flow.The final simulation results show the two station models’the worst location of stoppingwere the same one,which was that two train respectively stopped both end subway rail of station.After that,this paper analysed how the summer ventilation outdoor dry bulb temperature influenced temperature distribution.and the results show that critical summer ventilation temperatures of station having or no barrier door were30℃and29℃.It is essential job to fit linear formula about summer ventilation outdoor dry bulb temperature and average temperature of the platform area of two kinds of platform typeFinally,considering economical efficiency,utility and conditionality,this paper analysed how the ventilation hole number and position impacted on temperature distribution,and obtained the the optimal ventilation layout and arrangement of law.The paper stimulated fire condition of the optimal ventilation layout and the results met evacuation requirements.Finally based on the analysis results,the paper established emergency ventilation,which was that the station just ensure the downward wind speed1.5m/s at connecting port between platform and the concourse.