Research On Ventilation System Of Underground Taxi Garage In Railway Station

As a part of passenger traffic in large transport hub, underground garage in railway station has continuous flow of people and traffic compared to traditional garage. Especially for taxi underground garage, the amounts of pollutant continually emitting from the idling taxi increase greatly. Thus it’s necessary to design ventilation system reasonably so as to solve the problems of air quality in the garage.By the comparison and analysis of the air quality standard home and abroad, the air environmental goals were confirmed. For taxi garage, CO was focused in this paper. According to the people’s time staying in the garage, the1-h average CO limits of30mg/m3were used for the waiting area and the15-min average CO limits of86mg/m3were used for the traveling lane. Meanwhile, analyzed the factors effecting the quantity of the pollutants from vehicles, proposed calculating pollution emissions by the hourly traffic volume of traveling vehicles in different conditions.With an example of taxi underground garage in Chongqing railway station, the preliminary ventilation system of the garage are simulated by the PHOENICS software to analyze the fields of velocity, temperature and CO pollution. The results show that the centralized air supply outlet used in traditional underground garage is not conducive to the discharge of pollutions. Meanwhile, when adopting the air change rate of6, the ventilation environment can reach the requirements in general traffic flow, but can’t fulfill the demands in congestion traffic flow.The improvement measures are proposed aiming at the shortcomings of the preliminary design scheme. The theoretical calculation and simulation results of ventilation system in different air change rate indicate that the minimum air change rate is appropriately10times per hour for this garage in congestion traffic flow.By changing the form of air supply outlet, the simulation results show that adopting uniform air supply outlet mode can effectively improve the ventilation environment of underground taxi garage in railway station. In addition, by comparing the simulation results of five cases, drew the conclusions that roof air supply had effective improvements.Finally, changed the form of air exhaust outlet in the roof air supply outlet mode, and simulated seven cases in different heights and airflow distribution. The analysis indicate that the upper exhaust air distribution can get a better ventilation performance in underground taxi garage in railway station.