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Flow, Turbulence and Combustion

, Volume 96, Issue 2, pp 377–389 | Cite as

Spray-Flame Dynamics in a Rich Droplet Array

  • Colette NicoliEmail author
  • Pierre Haldenwang
  • Bruno Denet
Article

Abstract

We numerically study spray-flame dynamics. The initial state of the spray is schematized by alkane droplets located at the nodes of a face-centered 2D-lattice. The droplets are surrounded by a gaseous mixture of alkane and air. The lattice spacing s reduced by the combustion length scale is large enough to consider that the chemical reaction occurs in a heterogeneous medium. The overall spray equivalence ratio is denoted by ϕ T , with ϕ T = ϕ L + ϕ G , where ϕ G corresponds to the equivalence ratio of the gaseous surrounding mixture at the initial saturated partial pressure, while ϕ L is the so-called liquid loading. To model such a heterogenous combustion, the retained chemical scheme is a global irreversible one-step reaction governed by an Arrhenius law, with a modified heat of reaction depending on the local equivalence ratio. ϕ T is chosen in the range 0.9 ≤ ϕ T ≤ 2. Three geometries (s = 3, s = 6, s = 12) and four liquid loadings, ϕ L = 0.3, ϕ L = 0.5, ϕ L = 0.7, ϕ L = 0.85 are studied. In the rich sprays, our model qualitatively retrieves the recent experimental measurements: the rich spray-flames can propagate faster than the single-phase flames with the same overall equivalence ratio. To analyse the conditions for this enhancement, we introduce the concept of “spray Peclet number”, which compares the droplet vaporization time with the combustion propagation time of the single-phase flame spreading in the fresh surrounding mixture.

Keywords

Droplet combustion Heterogeneous combustion Reduced kinetics Spray-flame Two phase-combustion 

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References

  1. 1.
    Hayashi, S., Kumagai, S., Sakai, T.: Propagation velocity and structure of flames in droplet vapor air mixtures. Combust. Sci. Tech. 15, 169–177 (1976)CrossRefGoogle Scholar
  2. 2.
    Thimothee, R., Chauveau, C., Halter, F., Gokalp, I.: Characterization of cellular instabilities of a flame propagating in an aerosol. Proceedings of ASME Turbo Expo 2015: Turbine Technical Conference and Exposition GT2015 (2015)Google Scholar
  3. 3.
    Bradley, D., Lawes, M., Liao, S.Y., Saat, A.: Laminar mass burning and entrainment velocities and flame instabilities of isooctane, ethanol and hydrous ethanol/air aerosols. Combust. Flame 161(6), 1620–1632 (2014)CrossRefGoogle Scholar
  4. 4.
    Nicoli, C., Denet, B., Haldenwang, P.: Rich spray-flame propagating through a 2d-lattice of alkane droplets in air. Combust. Flame (2015)Google Scholar
  5. 5.
    Nomura, H., Koyama, M., Miyamoto, H., Ujiie, Y., Sato, J., Kono, M., Yoda, S.: Microgravity experiments of flame propagation in ethanol droplet vapor air mixture. Proc. Combust. Inst. 28, 999–1005 (2000)CrossRefGoogle Scholar
  6. 6.
    Nomura, H., Kawasumi, I., Ujiie, Y., Sato, J.: Effects of pressure on flame propagation in a premixture containing fine fuel droplets. Proc. Combust. Inst. 31, 2133–2140 (2007)CrossRefGoogle Scholar
  7. 7.
    Nicoli, C., Denet, B., Haldenwang, P.: Lean flame dynamics through a 2d lattice of alkane droplets in air. Combust. Sci. Tech. 186(2), 103–119 (2014a)CrossRefGoogle Scholar
  8. 8.
    Nicoli, C., Haldenwang, P., Denet, B.: Numerical study of flame dynamics through a 2d-lattice of alkane droplets in air. In: ECM2013: 6th European combustion meeting. Lund, Sweden (2013)Google Scholar
  9. 9.
    Nicoli, C., Haldenwang, P.: Analysis of one-step chemistry models for flame propagation in various equivalence ratio premixtures of high alkane-air. SPEIC10: Towards Sustainable Combustion, Tenerife (2010)Google Scholar
  10. 10.
    Nicoli, C., Haldenwang, P., Denet, B.: Numerical study of spray flames dynamics through a 2d-lattice of droplets in alkane-air mixtures. SPEIC14: Towards Sustainable Combustion, Lisboa (2014b)Google Scholar
  11. 11.
    Joulin, G., Mitani, J.: Linear stability analysis of two-reactant flames. Combust. Flame 40, 235–246 (1981)CrossRefGoogle Scholar
  12. 12.
    Garcia-Ybarra, P., Nicoli, C., Clavin, P.: Soret and dilution effects on premixed flames. Combust. Sci. Tech. 42, 235–246 (1984)Google Scholar
  13. 13.
    Denet, B., Haldenwang, P.: A numerical study of premixed flames darrieus-landau instability. Combust. Sci. Tech. 104, 143–167 (1995)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  • Colette Nicoli
    • 1
    Email author
  • Pierre Haldenwang
    • 1
  • Bruno Denet
    • 2
  1. 1.M2P2, UMR-CNRS 7340; CNRS-AMU -Ecole Centrale MarseilleMarseille Cedex 20France
  2. 2.IRPHE, Aix-Marseille-Université-CNRS-Ecole Centrale MarseilleMarseille Cedex 20France

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