A flammability limit model for hydrogen-air-diluent mixtures based on heat transfer characteristics in flame propagation

  • Jeon, Joongoo (Department of Nuclear Engineering, Hanyang University) ;
  • Choi, Wonjun (Department of Nuclear Engineering, Hanyang University) ;
  • Kim, Sung Joong (Department of Nuclear Engineering, Hanyang University)
  • Received : 2019.01.02
  • Accepted : 2019.05.02
  • Published : 2019.10.25


Predicting lower flammability limits (LFL) of hydrogen has become an ever-important task for safety of nuclear industry. While numerous experimental studies have been conducted, LFL results applicable for the harsh environment are still lack of information. Our aim is to develop a calculated non-adiabatic flame temperature (CNAFT) model to better predict LFL of hydrogen mixtures in nuclear power plant. The developed model is unique for incorporating radiative heat loss during flame propagation using the CNAFT coefficient derived through previous studies of flame propagation. Our new model is more consistent with the experimental results for various mixtures compared to the previous model, which relied on calculated adiabatic flame temperature (CAFT) to predict the LFL without any consideration of heat loss. Limitation of the previous model could be explained clearly based on the CNAFT coefficient magnitude. The prediction accuracy for hydrogen mixtures at elevated initial temperatures and high helium content was improved substantially. The model reliability was confirmed for $H_2-air$ mixtures up to $300^{\circ}C$ and $H_2-air-He$ mixtures up to 50 vol % helium concentration. Therefore, the CNAFT model developed based on radiation heat loss is expected as the practical method for predicting LFL in hydrogen risk analysis.




  1. T. Nishimura, H. Hoshi, A. Hotta, Current research and development activities on fission products and hydrogen risk after the accident at Fukushima Daiichi nuclear power station, Nucl. Eng. Technol 47 (2015) 1-10.
  2. S.W. Hong, J. Kim, H.-S. Kang, Y.-S. Na, J. Song, Research efforts for the resolution of hydrogen risk, Nucl. Eng. Technol 47 (2015) 33-46.
  3. N.K. Kim, J. Jeon, W. Choi, S.J. Kim, Systematic hydrogen risk analysis of OPR1000 containment before RPV failure under station blackout scenario, Ann. Nucl. Energy 116 (2018) 429-438.
  4. S. Gupta, Experimental investigations relevant for hydrogen and fission product issues raised by the Fukushima accident, Nucl. Eng. Technol 47 (2015) 11-25.
  5. A. Bentaib, N. Meynet, A. Bleyer, Overview on hydrogen risk research and development activities: methodology and open issues, Nucl. Eng. Technol 47 (2015) 26-32.
  6. D.Y. Kim, J.H. Kim, K.H. Yoo, M.G. Na, Prediction of hydrogen concentration in containment during severe accidents using fuzzy neural network, Nucl. Eng. Technol 47 (2015) 139-147.
  7. K. Malik et al., Detonation cell size model based on deep neural network for hydrogen, methane and propane mixtures with air and oxygen, Nucl. Eng. Technol.
  8. J. Yu, B. Hou, A. Lelyakin, Z. Xu, T. Jordan, Gas detonation cell width prediction model based on support vector regression, Nucl. Eng. Technol 49 (2017) 1423-1430.
  9. L.L. Humphries, R.K. Cole, D.L. Louie, V.G. Figueroa, M.F. Young, MELCOR Computer Code Manuals, Sandia National Laboratories, Albuquerque, USA, 2015. SAND2015-6692R.
  10. P. Nikolaidis, A. Poullikkas, A comparative overview of hydrogen production processes, Renew, Sustain. Energy Rev. 67 (2017) 597-611.
  11. A.L. Sanchez, F.A. Williams, Recent advances in understanding of flammability characteristics of hydrogen, Prog. Energy Combust. Sci. 41 (2014) 1-55.
  12. T. Ma, A thermal theory for estimating the flammability limits of a mixture, Fire Saf. J. 46 (2011) 558-567.
  13. D.B. Spalding, A theory of inflammability limits and flame-quenching, Proc. Roy. Soc. Lond. A 240 (1957) 83-100.
  14. M. Vidal, W. Wong, W.J. Rogers, M.S. Mannan, Evaluation of lower flammability limits of fuel-air-diluent mixtures using calculated adiabatic flame temperatures, J. Hazard Mater. 130 (2006) 21-27.
  15. M.G. Zabetakis, Flammability Characteristics of Combustible Gases and Vapors, US Bureau of Mines, Bulletin 627, Washington, 1965.
  16. T.K.H. Cheng, An Experimental Study of the Rich Flammability Limits of Some Gaseous Fuels and Their Mixtures in Air, MSc Thesis, Department of Mechanical Engineering, University of Calgary, 1985.
  17. S.O. Bade Shrestha, Systematic Approach to Calculations of Flammability Limits of Fuel-Diluent Mixtures in Air, MSc Thesis, Department of Mechanical Engineering, University of Calgary, 1992.
  18. G. Shu, B. Long, H. Tian, H. We, X. Liang, Flame temperature theory-based model for evaluation of the flammable zones of hydrocarbon-air-CO2 mixtures, J. Hazard Mater. 294 (2015) 137-144.
  19. M. Wu, G. Shu, R. Chen, H. Tian, X. Wang, Y. Wang, A new model based on adiabatic flame temperature for evaluation of the upper flammable limit of alkane-air-CO2 mixtures, J. Hazard Mater. 344 (2018) 450-457.
  20. Y. Ju, G. Masuya, P.D. Ronney, Effects of radiative emission and absorption on the propagation and extinction of premixed gas flames, Proc. Combust. Inst. 27 (1998) 2619-2626.
  21. M. Terpstra, Flammability Limits of Hydrogen-Diluent Mixtures in Air, MSc thesis, University of Calgary, 2012.
  22. R.K. Kumar, Flammability limits of hydrogen-oxygen-diluent mixtures, J. Fire Sci. 3.4 (1985) 245-262.
  23. J.E. Hustad, O.K. Sonju, Experimental studies of lower flammability limits of gases and mixtures of gases at elevated temperatures, Combust. Flame 71 (1998) 283-294.
  24. I. Glassman, R.A. Yetter, N.G. Glumac, Combustion, Academic press, 2015.
  25. H.F. Coward, G.W. Jones, Limits of Flammability of Gases and Vapors, US Bureau of Mines, Pittsburgh, Pennsylvania, USA, 1957. Bulletin 627.
  26. E.A. Ural, R.G. Zalosh, A mathematical model for lean hydrogen-air-steam mixture combustion in closed vessel, Proc. Combust. Inst. 20 (1984) 1727-1734.
  27. E. Mayer, A theory of flame propagation limits due to heat loss, Combust. Flame 1 (1957) 438-452.
  28. Z. Zhou, Y. Shoshin, F.E. Hernandez-Perez, et al., Experimental and numerical study of cap-like lean limit flames in $H_2-CH_4$-air mixtures, Combust. Flame 189 (2018) 212-224.
  29. D. Fernandez-Galisteo, A.L. Sanchez, A. Linan, F.A. Williams, The hydrogen-air burning rate near the lean flammability limit, Combust. Theor. Model 13 (2009) 741-761.
  30. H.J. Liaw, K.Y. Chen, A model for predicting temperature effect on flammability limits, Fuel 178 (2016) 179-187.
  31. K.P. Lakshmisha, P. Paul, H. Mukunda, On the flammability limit and heat loss in flames with detailed chemistry, Proc. Combust. Inst. 23 (1991) 433-440.
  32. Y. Shoshin, J. Jarosinski, On extinction mechanism of lean limit methane-air flame in a standard flammability tube, Proc. Combust. Inst. 32 (2009) 1043-1050.
  33. Y. Dong, A.T. Holley, M.G. Andac, et al., Extinction of premixed $H_2$/air flames: chemical kinetics and molecular diffusion effect, Combust. Flame 142 (2005) 374-387.
  34. R.M. Davies, G. Taylor, The mechanics of large bubbles rising through extended liquids and through liquids in tubes, Proc. R. Soc. A. Math. Phys. Eng. Sci. 200 375-390.
  35. A. Levy, An optical study of flacmmability limits, Proc. Roy. Soc. Lond. A 283 (1965) 134-145.
  36. B. Zhang, G. Xiu, C. Bai, Explosion characteristics of argon/nitrogen diluted natural gas-air mixtures, Fuel 124 (2014) 125-132.