Comparative Study on The Numerical Simulation for The Back-Layer of The Tunnel Fire-Driven Flow with LES and RANS

터널화재유동의 역기류 해석을 위한 LES 및 RANS 결과의 비교 고찰

  • 장용준 (한국철도기술연구원, 철도환경연구실) ;
  • 김학범 (한국철도기술연구원, 철도환경연구실) ;
  • 김진호 (한국철도기술연구원, 도시철도표준화연구단) ;
  • 한석윤 (한국철도기술연구원, 도시철도표준화연구단)
  • Published : 2009.03.01


In this study, comparative analysis on the back-layer phenomena in the tunnel-fire driven flow is performed using numerical simulation with LES and RANS. FDS(Fire Dynamics Simulator) code is employed to calculate the fire-driven turbulent flow for LES and Smartfire code is used for RANS. Hwang and Wargo's data of scaling tunnel fire experiment are employed to compare with the present numerical simulation. The modeled tunnel is 5.4m(L) ${\times}$ 0.4m(W) ${\times}$ 0.3m(H). Heat Release Rate (HRR) of fire is 3.3kW and ventilation-velocity is 0.33m/s in the main stream. The various grid-distributions are systematically tested with FDS code to analyze the effects of grid size. The LES method with FDS provides an improved back-layer flow behavior in comparison with the RANS (${\kappa}-{\epsilon}$) method by Smartfire. The FDS solvers, however, overpredict the velocity in the center region of flow which is caused by the defects in the tunnel-entrance turbulence strength and in the near-wall turbulent flow in FDS code.



  1. Hwang, C. C. and Edwards, J. C., 2005, "The Critical Ventilation Velocity in Tunnel Fires-A Computer Simulation," Fire Safety Journal 40. pp. 213-244
  2. Hwang, C. C. and Wargo, J. D., 1986, "Experimental Study of Thermally Generated Reverse Stratified Layers in a Fire Tunnel," Combustion and Flame, 66, pp. 171-180
  3. Woodburn, P. J. and Britter, R. E., 1996, "CFD Simulations of a Tunnel Fire-Part I," Fire Safety Journal, 26, pp. 35-62
  4. Woodburn, P. J. and Britter, R. E., 1996, "CFD Simulations of a Tunnel Fire-Part II," Fire Safety Journal, 26, pp. 63-90
  5. Jang, Y. J., Chen, H. C., and Han, J. C., 2001, "Computation of Flow and Heat Transfer in Two-Pass Channels with 60 deg Ribs," ASME Journal of Heat Transfer, Vol. 123, No. 3, pp. 563-575
  6. Jang, Y. J. and Leschziner, M. A., 2004, "An Investigation of Higher-Order Closures in The Computation of the Flow Around a Generic Car Body," ECCOMAS 2004 Congress, Jyvaskyla Paviljonki International Congress Centre and University of Jyvaskyla, Finland, 24 – 28 July
  7. Wang, C., Jang, Y. J. and Leschziner, M. A., 2004, "Modeling 2D and 3D Separation from Curved Surfaces with Anisotropy-Resolving Turbulence Closures," International Journal of Heat and Fluid Flow, Vol. 25, No. 3, pp. 499-512
  8. Abe, K., Jang, Y. J. and Leschziner, M. A., 2003, "An Investigation of Wall-Anisotropy Expressions and Length-Scale Equations for Non-Linear Eddy- iscosity Models," International Journal of Heat and Fluid Flow, Vol. 24, pp. 181-198
  9. Jang, Y. J., Leschziner M. A., Abe, K. and Temmerman, L., 2002, "Investigation of Anisotropy-Resolving Turbulence Models by Reference to Highly-Resolved LES Data for Separated Flows," Flow, Turbulence and Combustion, Vol. 69, pp. 161-203
  10. Dejoan, A., Jang, Y. J., and Leschziner, M. A., 2005, "Comparative LES and Unsteady RANS Computations for a Periodically-Perturbed Separated Flow Over a Backward-Facing Step," ASME Journal of Fluids Engineering, Vol. 127, pp. 872-878
  11. Temmerman, L., Leschziner, M. A., Mellon, C. P. and Frohlich, J., 2003, "Investigation of Wall-Function Approximation and Subgrid-Scale Models in Large Eddy Simulation of Separated Flow in a Channel with Streamwise Periodic Constrictions," International Journal of Heat and Fluid Flow, Vol. 24, pp. 157-180
  12. McGrattan, K. B., 2006, "Fire Dynamics Simulator(Version 4) Technical Reference Guide," NIST, March
  13. McGrattan, K. B. and Forney, Glenn, 2006, "Fire Dynamics Simulator(Version 4) User's Guide," NIST, March
  14. McGrattan, K. B., Baum H. R. and Rehm R. G., 1998, "Large Eddy Simulation of Smoke Movement," Fire Safety Journal, 30, pp. 161-178
  15. McGrattan, K. B., Rehm R. G. and Baum H. R., 1994, "Fire-Driven Flows in Enclosures," Journal of Computational Physics, 110, pp. 285-291
  16. Ewer, J., Jia, F., Grandision, A., Galea, E. and Patel, M., 2004, "Smartfire V4.0 Technical Reference Manual," U.G.M.T, August
  17. Ewer, J., Jia, F., Grandision, A., Galea, E. and Patel, M., 2004, "Smartfire V4.0 User Guide for the Smartfire Environment," U.G.M.T, September
  18. Ko, Kyung-Chan and Park, Woe-Chul, 2004, "A Numerical Study of a Room Fire for Fire Sizes I. Center Fire," Journal of the KIIS, Vol. 19, No. 1, pp. 18-22
  19. Jang, Yong-Jun and Park, Won-Hee, 2007, "The Applicability Analysis of FDS Code for Fire-Driven Flow Simulation in Railway Tunnel," Journal of the korean society for railway, Vol. 10, No. 2, pp. 224-230
  20. Jang, Yong-Jun, 2006, “Three-Dimensional Flow Analysis Around Rolling Stock with Square Cross Section Using Low Re ${\kappa}-{\epsilon}$," Journal of the korean society for railway, Vol. 9, No. 6, pp. 772-777
  21. Lien, F. S., and Leschziner, M. A., 1994a, "A General Non-Orthogonal Collocated Finite Algorithm for Turbulent Flow at All Speeds Incorporating Second-Moment Turbulence-Transport Closure, Part 1: Computational Implementation," Comput. Methods Appl. Mech. Engr., Vol. 114, pp. 123-148
  22. Lien, F. S., and Leschziner, M. A. 1994b, "Upstream Monotonic Interpolation for Scalar Transport with Application to Complex Turbulent Flows," International Journal of Numerical Methods in Fluids, Vol. 19, pp. 527-548

Cited by