We present a minimal model of spray combustion to investigate a flame front propagating through a fuel-lean mixture of fuel vapor, droplets and air. The model relies on a main control parameter, Da, named the Damkoehler number, which allows us to take into account a large variety of fuel sprays. Numerical results reveal, as a function of Da, a wide range of spray-flame structures, including the classical gaseous premixed flame, a specific regime controlled by vaporisation, and a pulsating mode of propagation. The latter appears when the vaporisation is smaller than (or equal to) the reaction time, and it occurs even with a unit Lewis number.
Un modéle minimal pour la combustion des brouillards est présenté. Il permet d'étudier la propagation d'une flamme à travers un milieu pauvre en hydrocarbure, constitué de vapeur, de gouttelettes et d'air. Il met en évidence, comme paramètre principal, le nombre de Damkoehler (Da), dont la variation nous permet d'étudier de nombreuses configurations de combustion des brouillards. Les résultats numériques font apparaı̂tre plusieurs régimes de flammes : le classique mode de propagation des flammes de prémélange gazeux, un régime spécifique contrôlé par l'évaporation et un mode de propagation pulsant. Ce dernier apparaı̂t lorsque le taux d'évaporation est supérieur ou égal au taux de réaction chimique (Da⩽O(1)), et ce, même quand le nombre de Lewis vaut un.
Mots-clés : Combustion, Combustion des brouillards, Evaporation, Flammes pulsantes
Sylvain Suard 1; Pierre Haldenwang 1; Colette Nicoli 1
@article{CRMECA_2004__332_5-6_387_0, author = {Sylvain Suard and Pierre Haldenwang and Colette Nicoli}, title = {Different spreading regimes of spray-flames}, journal = {Comptes Rendus. M\'ecanique}, pages = {387--396}, publisher = {Elsevier}, volume = {332}, number = {5-6}, year = {2004}, doi = {10.1016/j.crme.2004.02.004}, language = {en}, }
Sylvain Suard; Pierre Haldenwang; Colette Nicoli. Different spreading regimes of spray-flames. Comptes Rendus. Mécanique, Microgravity / La micropesanteur, Volume 332 (2004) no. 5-6, pp. 387-396. doi : 10.1016/j.crme.2004.02.004. https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.1016/j.crme.2004.02.004/
[1] The effect of drop size on flame propagation in liquid aerosols, Proc. Roy. Soc. London Ser. A, Volume 225 (1954), pp. 357-392
[2] Combustion of fuel vapor-drop–air systems. 1. Open burner flames combus, Flame, Volume 20 (1973), pp. 343-350
[3] Flame propagation in fuel droplet-vapor–air mixtures, Fifteenth Symposium (International) on Combustion (The Combustion Institute), Volume 15 (1974), pp. 445-452 (in:)
[4] Effect of droplet size on burning velocity of kerosine–air sprays, Combust. Flame, Volume 25 (1975), pp. 247-257
[5] Propagation velocity and structure of flames in droplet-vapor–air mixtures, Combust. Sci. Tech., Volume 15 (1976), pp. 169-177
[6] Flame propagation in heterogeneous mixtures of fuel droplets, fuel vapor and air, Eighteenth Symposium (International) on Combustion (The Combustion Institute), Volume 18 (1981), pp. 321-328 (in:)
[7] Flame propagation in heterogeneous mixtures of fuel drops and air, Combust. Flame, Volume 66 (1986), pp. 193-210
[8] Instability of a flame front propagating through a fuel-rich droplet-vapour–air cloud, Combust. Theory Modelling, Volume 3 (1999), pp. 567-584
[9] F. Atzler, Fundamental studies of aerosol combustion, Ph.D. thesis, School of Mechanical Engineering, University of Leeds, 1999
[10] Limiting factor of flame propagation in low-volatility fuel clouds, Eighteenth Symposium (International) on Combustion (The Combustion Institute), Volume 18 (1981), pp. 361-367 (in:)
[11] Flame propagation in a one-dimensional liquid fuel spray, Combust. Sci. Tech., Volume 9 (1974), pp. 197-207
[12] Vaporisation controlled regime of flames propagating in fuel-lean sprays, J. Phys. IV, Volume 11 (2001), pp. 301-310
[13] Flame propagation in aerosols of fuel droplets, fuel vapor and air, Combust. Sci. Tech., Volume 40 (1984), pp. 217-232
[14] Theory of laminar flame propagation in off-stoichiometric dilute sprays, Int. J. Heat Mass Transfer, Volume 31 (1988), p. 1023
[15] Linear stability of laminar premixed spray flames, Proc. Roy. Soc. London Ser. A, Volume 457 (2001), pp. 1-31
[16] Evaporation and combustion of sprays, Prog. Energy Combust. Sci., Volume 9 (1983), pp. 1-76
[17] Linear stability analysis of nonadiabatic flames: diffusional-thermal model, Combust. Flame, Volume 25 (1979), pp. 247-257
[18] P. Berthonnaud, K. Domelevo, J.-M. Roquejoffre, Stability of travelling wave solutions in a one dimensional two-phase flow combustion model, in preparation
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