CFD Simulation to Study the Effect of Ambient Temperature on the Ventilation in a Metro Tunnel

Authors: Yousif Naif Almutai, Yajue Wu

Abstract:

In larger cities worldwide, mass transportation systems, including underground systems, have grown to account for the majority of travel in those settings. Underground networks are vulnerable to fires, however, endangering travellers’ safety, with various examples of fire outbreaks in this setting. This study aims to increase knowledge of the impacts of extreme climatic conditions on fires, including the role of the high ambient temperatures experienced in Middle Eastern countries and specifically in Saudi Arabia. This is an element that is not always included when assessments of fire safety are made (considering visibility, temperatures, and flows of smoke). This paper focuses on a tunnel within Riyadh’s underground system as a case study and includes simulations based on computational fluid dynamics using ANSYS Fluent, which investigates the impact of various ventilation systems while identifying smoke density, speed, pressure and temperatures within this tunnel.

Keywords: Fire, subway tunnel, CFD, ventilation, smoke concentration, harsh weather.

References:

[1] Teodosiu, C., Ilie, V., Dumitru, R. and Teodosiu, R., 2015. Assessment of ventilation efficiency for emergency situations in subway systems by CFD modeling. Building Simulation, 9(3), pp.319-334.
[2] Alarie, Y.C. (2002). Toxicity of Fire Smoke.
[3] Wu, J. and Shen, F. (2016) “Experimental study on the effects of ventilation on smoke movement in tunnel fires,” International Journal of Ventilation, 15(1), pp. 94–103. Available at: https://doi.org/10.1080/14733315.2016.1173295.
[4] Drysdale, D.D., Macmillan, A.J.R. and Shilitto, D. (1992) “The King's Cross Fire: Experimental Verification of the ‘trench effect,’” Fire Safety Journal, 18(1), pp. 75–82. Available at: https://doi.org/10.1016/0379-7112(92)90048-h.
[5] Sturm, P., Beyer, M. and Rafiei, M. (2017). On the problem of ventilation control in case of a tunnel fire event. Case Studies in Fire Safety, 7, pp.36–43. doi:10.1016/j.csfs.2015.11.001.
[6] Tsai, K.-C., Lee, Y.-P. and Lee, S.-K. (2011) “Critical ventilation velocity for tunnel fires occurring near tunnel exits,” Fire Safety Journal, 46(8), pp. 556–557. Available at: https://doi.org/10.1016/j.firesaf.2011.08.003.
[7] Jagger S, Grant G (2005). Use of tunnel ventilation for fire safety. In: Beard A, Carvel R (eds), The Handbook of Tunnel Fire Safety (Chapter 8, pp. 163 − 183). London: Thomas Telford.
[8] Danziger N H, Kennedy W D (1982) “Proceedings of the 4th International Symposium Aerodynamics and Ventilation of Vehicle Tunnels,”. (York, UK 1982)
[9] Wu, Y. and Bakar, M.Z.A. (2000) “Control of smoke flow in tunnel fires using longitudinal ventilation systems – a study of the critical velocity,” Fire Safety Journal, 35(4), pp. 363–390. Available at: https://doi.org/10.1016/s0379-7112(00)00031-x.
[10] Hakimzadeh, B. and Talaee, M.R. (2018). Analysis of a new strategy for emergency ventilation and escape scenario in long railway tunnels in the fire mode. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 233(3), pp.239–250. doi:10.1177/0954409718789541.
[11] Ingason, H.; Li, Y.Z. Model scale tunnel fire tests with longitudinal ventilation. Fire Saf. J. 2010, 45, 371–384.
[12] Król, A. and Król, M. (2021) “Some tips on numerical modeling of airflow and fires in Road Tunnels,” Energies, 14(9), p. 2366. Available at: https://doi.org/10.3390/en14092366.
[13] Teodosiu C, Ilie V, Teodosiu R. Appropriate CFD Turbulence Model for Improving Indoor Air Quality of Ventilated Spaces. Mathematical Modelling in Civil Engineering 2014;10:28-42.
[14] Pflitsch, A., Brune, M., Steiling, B., Killing-Heinze, M., Agnew, B., Irving, M., & Lockhart, J. (2012). ¨ Air flow measurements in the underground section of a UK light rail system. Applied Thermal Engineering, 32, 22–30. doi:10.1016/j.applthermaleng.2011.07.030
[15] Ahmed Hussein Hafez, Tamer Heshmat Mohamed Aly Kasem, Basman Elhadidi, and Mohamed Madbouly Abdelrahman, “Modelling Three Dimensional Unsteady Turbulent HVAC Induced Flow”, J. Adv. Res. Fluid Mech. Therm. Sc., vol. 87, no. 1, pp. 76–90, Sep. 2021.
[16] Li, Ying, and Haukur Ingason. 2010. “Study of Critical Velocity and Backlayering Length in Longitudinally Ventilated Tunnel Fires.” Fire Safety Journal - FIRE SAFETY J 45 (November): 361–70. https://doi.org/10.1016/j.firesaf.2010.07.003.