Ventilation Efficiency in the Subway Environment for the Indoor Air Quality
Clean air in subway station is important to passengers. The Platform Screen Doors (PSDs) can improve indoor air quality in the subway station; however the air quality in the subway tunnel is degraded. The subway tunnel has high CO2 concentration and indoor particulate matter (PM) value. The Indoor Air Quality (IAQ) level in subway environment degrades by increasing the frequency of the train operation and the number of the train. The ventilation systems of the subway tunnel need improvements to have better air-quality. Numerical analyses might be effective tools to analyze the performance of subway twin-track tunnel ventilation systems. An existing subway twin-track tunnel in the metropolitan Seoul subway system is chosen for the numerical simulations. The ANSYS CFX software is used for unsteady computations of the airflow inside the twin-track tunnel when the train moves. The airflow inside the tunnel is simulated when one train runs and two trains run at the same time in the tunnel. The piston-effect inside the tunnel is analyzed when all shafts function as the natural ventilation shaft. The supplied air through the shafts is mixed with the pollutant air in the tunnel. The pollutant air is exhausted by the mechanical ventilation shafts. The supplied and discharged airs are balanced when only one train runs in the twin-track tunnel. The pollutant air in the tunnel is high when two trains run simultaneously in opposite direction and all shafts functioned as the natural shaft cases when there are no electrical power supplies in the shafts. The remained pollutant air inside the tunnel enters into the station platform when the doors are opened.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1058519Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 3707
 H. L.Karlsson, L. Nilsson,and L. Moller, 2005, “Subway particle are more genotoxic than street particles and induce oxidative stress in cultured human lung cells”, Chem. Res. Toxicol, vol. 18, pp. 19-23.
 F.D.Yuan, and S.J.You, 2007, “CFD simulation and optimization of the ventilation for subway side-platform”, Tunnelling and Underground Space Technology, vol. 22, pp. 474-482.
 J. S. M. Li, and W. K. Chow, 2003, “Numerical studies on performance evaluation of tunnel ventilation safety systems”, Tunnelling and Underground Space Technology, vol.18, pp. 435-452.
 J.Modic, 2003, “Fire simulation in road tunnels”, Tunnelling and Underground Space Technology”, vol. 18, pp. 525-530.
 J. H. Lee, and M. D. Oh, 1998, "Train Wind in the Subway Tunnel“, The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea, vol.27, pp. 109~114 (in Korean).
 J. Song, H. Lee, S. Kim, and D. Kim, 2008, “How about the IAQ in subway environment and its management?” Asian Journal of Atmospheric Environment, vol. 2-1, pp. 60-67.
 ANSYS CFX, 2009, ANSYS Workbench, ICEM-CFD, CFX-Pre, CFX-Solver, CFX-Post User’s Manual.
 J.Y.Kim, and K.Y.Kim, 2007, “Experimental and numerical analyses of train-induced unsteady tunnel flow in subway”, Tunnelling and Underground Space Technology”, vol.22, pp. 166-172.
 F.R. Menter, 1994, “Two-equation eddy-viscosity turbulence models for engineering applications” AIAA-Journal., vol.32, pp. 269-289.
 Final report of Seoul Metropolitan Subway Corporation, 2010, “Developing technology for pollution control of subway tunnel”
 S. Tokarek, and A.Bernis, 2006, “An example of particle concentration reduction in Parisian subway stations by electrostatic precipitation”, Environmental Technology, vol.27, pp. 1279-1287.
 Y.D.Huang, W.Gao, and C.N.Kim, 2010, “A numerical study of the train-induced unsteady airflow in a subway tunnel with natural ventilation ducts using the dynamic layering method”, Journal of Hydrodynamics, vol. 22, pp.164-172.