Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31324
Numerical Simulation in the Air-Curtain Installed Subway Tunnel for the Indoor Air Quality

Authors: Kyung Jin Ryu, Makhsuda Juraeva, Sang-Hyun Jeong, Dong Joo Song

Abstract:

The Platform Screen Doors improve Indoor Air Quality (IAQ) in the subway station; however, and the air quality is degraded in the subway tunnel. CO2 concentration and indoor particulate matter value are high in the tunnel. The IAQ level in subway tunnel degrades by increasing the train movements. Air-curtain installation reduces dusts, particles and moving toxic smokes and permits traffic by generating virtual wall. The ventilation systems of the subway tunnel need improvements to have better air-quality. Numerical analyses might be effective tools analyze the flowfield inside the air-curtain installed subway tunnel. The ANSYS CFX software is used for steady computations of the airflow inside the tunnel. The single-track subway tunnel has the natural shaft, the mechanical shaft, and the PSDs installed stations. The height and width of the tunnel are 6.0 m and 4.0 m respectively. The tunnel is 400 m long and the air-curtain is installed at the top of the tunnel. The thickness and the width of the air-curtain are 0.08 m and 4 m respectively. The velocity of the air-curtain changes between 20 - 30 m/s. Three cases are analyzed depending on the installing location of the air-curtain. The discharged-air through the natural shafts increases as the velocity of the air-curtain increases when the air-curtain is installed between the mechanical and the natural shafts. The pollutant-air is exhausted by the mechanical and the natural shafts and remained air is pushed toward tunnel end. The discharged-air through the natural shaft is low when the air-curtain installed before the natural shaft. The mass flow rate decreases in the tunnel after the mechanical shaft as the air-curtain velocity increases. The computational results of the air-curtain installed tunnel become basis for the optimum design study. The air-curtain installing location is chosen between the mechanical and the natural shafts. The velocity of the air-curtain is fixed as 25 m/s. The thickness and the blowing angles of the air-curtain are the design variables for the optimum design study. The object function of the design optimization is maximizing the discharged air through the natural shaft.

Keywords: Indoor Air Quality, air-curtain, single-track subway tunnel

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1058259

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2323

References:


[1] 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).
[2] 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.
[3] Roberson P., and Shaw BH., 1978, "The linear air curtain as a particulate barrier", Journal of Environmental Science, vol.21, pp.32-33
[4] 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.
[5] Gupta, S., Pavageau, M., and Elicer-Cortes, J.C., 2006, "Cellular confinement of tunnel sections between two air curtains", Building and Environment, vol. 42, pp.3352-3365
[6] ANSYS CFX, 2009, ANSYS Workbench, ICEM-CFD, CFX-Pre, CFX-Solver, CFX-Post User-s Manual.
[7] Guyonnaud, L, Solliec, C, Dufresne de Virel, M and Rey, C, 2000, "Design of air curtains used for area confinement in tunnels", Experiments in Fluids, vol. 28, pp.377-384
[8] F.R. Menter, 1994, "Two-equation eddy-viscosity turbulence models for engineering applications" AIAA-Journal., vol.32, pp. 269-289.
[9] 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.
[10] 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.
[11] J. Modic, 2003, "Fire simulation in road tunnels", Tunnelling and Underground Space Technology", vol. 18, pp. 525-530.