Numerical studies on the synergistic effects of smoke extraction and control performance by mechanical ventilation shafts during tunnel fires

Abstract

High smoke extraction efficiency and a relatively stable smoke layer stratification are both expected in tunnel ventilation systems. The purpose of this paper is to explore the overall performance of mechanical board-coupled shaft under different ventilation strategies. A total of 57 simulations were conducted, and the effects of the distance between the shaft and board () and ventilation velocity on the overall performance were investigated. The results indicate that the performance of smoke extraction and control will be improved by the application of mechanical ventilation and board. Smoke movement patterns under different working conditions were different, for cases of the smoke could propagate through the whole tunnel without backflow, while for cases of, the backflow exists and the smoke movement can be separated into three periods (propagation, stagnation, and retraction). The critical criterion of backflow was investigated and a simple model was deduced to estimate the maximum propagation length. Moreover, the dimensionless time for the smoke flow to reach its maximum propagation length was established. Finally, a comprehensive index was proposed to evaluate the synergistic effects of smoke extraction and control performance. These studies may provide positive significance for the ventilation design.

Keywords

Tunnel fire / Smoke extraction / Smoke control / Ventilation shafts / Transient propagation

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

CRediT authorship contribution statement

Bin Zhu: Conceptualization, Investigation, Methodology, Writing - original draft. Haiyong Cong: Conceptualization, Funding acquisition, Writing - review & editing. Zhuyu Shao: Investigation, Writing - review & editing. Hairuo Hu: Investigation, Writing - review & editing. Lili Ye: Writing - review & editing. Yubo Bi: Writing - review & editing. Yiping Zeng: Writing - review & editing.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgement

This work was supported by the National Natural Science Foundation of China (Grant No. 51906030), the National Key R&D Program of China (Grant No. 2021YFB4000904), and the Opening Fund of State Key Laboratory of Fire Science (Grant Nos. HZ2019-KF07 and HZ2020-KF03).

References

[1] Cong, H. Y., Bi, M. S., Bi, Y. B., Li, Y. C., Jiang, H. P., & Gao, W. (2021). Experimental studies on the smoke extraction and smoke control performance by the ventilation shaft in extra-long road tunnels. International Journal of Thermal Sciences, 160, 106677.

[2] Cong, H. Y., Wang, X. S., Kong, X. X., & Xu, H. L. (2019). Effects of fire source position on smoke extraction efficiency by natural ventilation through a board-coupled shaft during tunnel fires. Proceedings of the Combustion Institute, 37(3), 3975-3984.

[3] Cong, H. Y., Wang, X. S., Zhu, P., Jiang, T. H., & Shi, X. J. (2017). Improvement in smoke extraction efficiency by natural ventilation through a board-coupled shaft during tunnel fires. Applied Thermal Engineering, 118, 127-137.

[4] Cong, H. Y., Wang, X. S., Zhu, P., Jiang, T. H., & Shi, X. J. (2018). Experimental study of the influences of board size and position on smoke extraction efficiency by natural ventilation through a boardcoupled shaft during tunnel fires. Applied Thermal Engineering, 128, 614-624.

[5] Chen, L. F., Hu, L. H., Zhang, X. L., Zhang, X. Z., Zhang, X. C., & Yang, L. Z. (2015). Thermal buoyant smoke back-layering flow length in a longitudinal ventilated tunnel with ceiling extraction at difference distance from heat source. Applied Thermal Engineering, 78(5), 129-135.

[6] Du, T., Du, J. X., Yang, D., Dong, S., & Yang, L. L. (2018). Transient evolution and backlayering of buoyancy-driven contaminants in a narrow inclined space. Building and Environment, 143, 59-70.

[7] Fan, C. G., Li, X. Y., Mu, Y., Guo, F. Y., & Ji, J. (2017). Smoke movement characteristics under stack effect in a mine laneway fire. Applied Thermal Engineering, 110, 70-79.

[8] Fan, C. G., & Yang, J. (2017). Experimental study on thermal smoke backlayering length with an impinging flame under the tunnel ceiling. Experimental Thermal and Fluid Science, 82, 262-268.

[9] Guo, C., Xu, J. F., Yang, L., Guo, X., Zhang, Y. L., & Wang, M. N. (2017). Energy-saving network ventilation technology of extra-long tunnel in climate separation zone. Applied Sciences, 7(5), 454.

[10] Guo, Q. H., Li, Y. Z., Ingason, H., Yan, Z. G., & Zhu, H. H. (2021). Theoretical and numerical study on mass flow rates of smoke exhausted from short vertical shafts in naturally ventilated urban road tunnel fires. Tunnelling and Underground Space Technology, 111, 103782.

[11] He, K., Shi, L., Zhang, S., Cong, W., Yang, H., & Cheng, X. (2023). Experimental study on temperature attenuation of smoke flow driven by dual fire sources in a tunnel. Tunnelling and Underground Space Technology, 134, 105004.

[12] He, L., Xu, Z., Markert, F., Zhao, J., Liu, Q., Tao, H., Wang, Z., & Fan, C. (2020). Experimental study of heat exhaust efficiency with natural ventilation in tunnel fire: Impact of shaft height and heat release rate. Journal of Wind Engineering and Industrial Aerodynamics, 201, 104173.

[13] Heselden, A. J. M. (1976). Studies of fire and smoke behaviour relevant to tunnels. Richmond: The National Archives.

[14] Homma, T., & Saltelli, A. (1996). Importance measures in global sensitivity analysis of nonlinear models. Reliability Engineering & System Safety, 52(1), 1-17.

[15] Hu, L. H., Huo, R., Li, Y. Z., Wang, H. B., & Chow, W. K. (2005). Fullscale burning tests on studying smoke temperature and velocity along a corridor. Tunnelling and Underground Space Technology, 20(3), 223-229.

[16] Hu, L. H., Huo, R., & Chow, W. K. (2008). Studies on buoyancy-driven back-layering flow in tunnel fires. Experimental Thermal and Fluid Science, 32(8), 1468-1483.

[17] Ingason, H., & Li, Y. Z. (2014). Tunnel fire dynamics. Springer.

[18] Ji, J., Gao, Z. H., Fan, C. G., Zhong, W., & Sun, J. H. (2012). A study of the effect of plug-holing and boundary layer separation on natural ventilation with vertical shaft in urban road tunnel fires. International Journal of Heat and Mass Transfer, 55(21-22), 6032-6041.

[19] Kikumoto, T., Kawabata, N., Maruyama, D., & Yamada, M. (2007). Model tests on fire smoke behavior in a small road tunnel for passenger cars. Proceedings of the Japan Society of Civil Engineers, 63 (3), 361-373 (in Japanese).

[20] Kunsch, J. P. (1998). Critical velocity and range of a fire-gas plume in a ventilated tunnel. Atmospheric Environment, 33(1), 13-24.

[21] Li, P., & Yang, D. (2020). Critical fan-induced pressure rise for preventing smoke flow multiplicity in longitudinally ventilated sloping tunnel fires: Potential function analysis and numerical simulations. Tunnelling and Underground Space Technology, 97, 103294.

[22] Li, Y. Z., Lei, B., & Ingason, H. (2010). Study of critical velocity and backlayering length in longitudinally ventilated tunnel fires. Fire Safety Journal, 45(6-8), 361-370.

[23] Li, Y. Z., & Ingason, H. (2018). Overview of research on fire safety in underground road and railway tunnels. Tunnelling and Underground Space Technology, 81, 568-589.

[24] McGrattan, K., McDermott, R., & Vanella, M. (2013). Fire dynamics simulator user’s guide. NIST Special Publication 1019.

[25] Mizutani, T., & Horiuchi, K. (1988). Fire tests in a tunnel with semitransverse ventilation system (Technical Note of PWRI, No. 2562). Public Works Research Institute https://thesis.pwri.go.jp/public_detail/101853. (in Japanese)

[26] Ministry of Transport of the People’s Republic of China (2014). JTG/T D70/2-02—2014: Guidelines for design of ventilation of highway tunnels. Beijing (in Chinese).

[27] Nyman, H., & Ingason, H. (2012). Temperature stratification in tunnels. Fire Safety Journal, 48, 30-37.

[28] Oka, Y., & Oka, H. (2016). Velocity and temperature attenuation of a ceiling-jet along a horizontal tunnel with a flat ceiling and natural ventilation. Tunnelling and Underground Space Technology, 56, 79-89.

[29] Saltelli, A. (2002). Sensitivity analysis for importance assessment. Risk Analysis, 22(3), 579-590.

[30] Tang, F., Li, L. J., Mei, F. Z., & Dong, M. S. (2016). Thermal smoke back-layering flow length with ceiling extraction at upstream side of fire source in a longitudinal ventilated tunnel. Applied Thermal Engineering, 106, 125-130.

[31] Vauquelin, O., & Mégret, O. (2002). Smoke extraction experiments in case of fire in a tunnel. Fire Safety Journal, 37(5), 525-533.

[32] Wang, M. N., Guo, X. H., Yu, L., Zhang, Y. T., & Tian, Y. (2021). Experimental and numerical studies on the smoke extraction strategies by longitudinal ventilation with shafts during tunnel fire. Tunnelling and Underground Space Technology, 116, 104030.

[33] Wang, Y. F., Jiang, J. C., & Zhu, D. Z. (2009). Full-scale experiment research and theoretical study for fires in tunnels with roof openings. Fire Safety Journal, 44(3), 339-348.

[34] Xie, B. C., Han, Y. X., Huang, H., Chen, L. N., Zhou, Y.,Fan, C. G., et al. (2018). Numerical study of natural ventilation in urban shallow tunnels: Impact of shaft cross section. Sustainable Cities and Society, 42, 521-537.

[35] Yao, Y. Z., Li, Y. Z., Ingason, H., & Cheng, X. D. (2019). Numerical study on overall smoke control using naturally ventilated shafts during fires in a road tunnel. International Journal of Thermal Sciences, 140, 491-504.

[36] Zhao, S., Li, Y. Z., Ingason, H., & Liu, F. (2019). A theoretical and experimental study on the buoyancy-driven smoke flow in a tunnel with vertical shafts. International Journal of Thermal Sciences, 141, 33-46.

[37] Zhu, Y., Tang, F., Chen, L., Wang, Q., & Xu, X. (2020). Effect of lateral concentrated smoke extraction on the smoke back-layering length and critical velocity in a longitudinal ventilation tunnel. Journal of Wind Engineering and Industrial Aerodynamics, 207, 104403.