Advertisement

Combustion, Explosion and Shock Waves

, Volume 42, Issue 2, pp 158–169 | Cite as

Metal-particle ignition and oxide-layer instability

  • D. Meinköhn
Article

Abstract

The use of metals as high-energy fuel additives is generally compromised by the appearance of a strongly protective oxide layer that covers the fuel surface. The previous work concentrated on the elimination of the oxide layer by a global, symmetry-conserving attack, using an admixture of aggressive chemical constituents in the ambient atmosphere, a strong flux of radiation, or strongly shearing gas flows designed to intensely strain the surface layer. This paper shows that symmetry breaking leads to a different approach to ignition. For a liquid oxide layer, destabilization can be obtained via the Marangoni effect associated with longitudinal surface stress, thus breaking the translational symmetry in longitudinal directions. The thermodynamic state of the layer is described in a thin-film model, which leads to a creeping-flow approximation. Ignition by way of the Marangoni effect is then shown to result from spreading of punctures and ruptures in the oxide layer, which is a prerequisite for layer thinning or even complete layer removal. Boron-particle ignition is selected to illustrate the theory, because the well-known difficulties with boron ignitability have greatly impaired the use of boron fuel in propulsion devices. It is shown that, for ambient temperatures below 1634 K, the oxide surface layer can be destabilized by way of punctures and ruptures, owing to the peculiar property of the boron oxide, namely, positive Marangoni numbers. Previous models of boron-particle ignition insisted on conservation of symmetry and expressly excluded the appearance of punctures and ruptures. Because of this constraint, a critical ambient temperature of 1900 K for boron ignition was obtained, so that the new value of 1634 K opens up a novel approach to ignition.

Key words

ignitability assisted ignition stability boron particles 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    W. Zhou, R. A. Yetter, F. L. Dryer, et al., “A comprehensive physical and numerical model of boron particle ignition,” in: Proc. 26th Int. Symp. on Combustion (1996), pp. 1909–1917.Google Scholar
  2. 2.
    G. Mohan and F. A. Williams, “Ignition and combustion of boron in O2/inert atmospheres,” AIAA J., 10, 776–783 (1972).Google Scholar
  3. 3.
    A. N. Zolotko, A. M. Matsko, D. I. Poleshchuk, et al., “Ignition of a two-component gas suspension of metal particles,” Combust., Expl., Shock Waves, 16, No. 1, 20–23 (1980).Google Scholar
  4. 4.
    D. A. Frank-Kamenetskii, Diffusion and Heat Transfer in Chemical Kinetics, Plenum, New York (1969).Google Scholar
  5. 5.
    I. Glassman, F. A. Williams, and P. Antaki, “A physical and chemical interpretation of boron particle combustion,” in: Proc. 20th Combustion Symp. (1984), pp. 2057–2064.Google Scholar
  6. 6.
    A. L. Breiter, V. M. Mal’tsev, and E. I. Popov, “Models of metal ignition,” Combust., Expl., Shock Waves, 13, No. 4, 475–484 (1977).Google Scholar
  7. 7.
    V. I. Rozenband and N. I. Vaganova, “A strength model of heterogeneous ignition of metal particles,” Combust. Flame, 88, 113–118 (1992).CrossRefGoogle Scholar
  8. 8.
    D. A. Yagodnikov and A. V. Voronetskii, “Experimental and theoretical study of the ignition and combustion of an aerosol of encapsulated aluminum particles,” Combust., Expl., Shock Waves, 33, No. 1, 49–55 (1997).Google Scholar
  9. 9.
    S. H. Davis, “Thermocapillary instabilities,” Ann. Rev. Fluid Mech., 19, 403–435 (1987).CrossRefADSMATHGoogle Scholar
  10. 10.
    D. Meinköhn, “Liquid oxide surface layers in metal combustion,” Combust. Theory Model., 8, 315–338 (2004).CrossRefADSGoogle Scholar
  11. 11.
    L. M. Pismen, “Symmetry breaking and pattern selection,” in: V. Hlavacek (ed.), Chemical Engineering: Concepts and Reviews (Dynamics of Nonlinear Systems), Gordon and Breach, New York (1986), pp. 47–83.Google Scholar
  12. 12.
    F. A. Williams, Combustion Theory, 2nd ed., Benjamin-Cummings, Menlo Park (1985).Google Scholar
  13. 13.
    D. Z. Safaneev, L. Ya. Kashporov, and Yu. M. Grigor’ev, “Heat-liberation kinetics in boron-oxygen interaction,” Combust., Expl., Shock Waves, 17, No. 2, 210–214 (1981).CrossRefGoogle Scholar
  14. 14.
    M. K. King, “Ignition and combustion of boron particles and clouds,” J. Spacecraft, 19, 294–306 (1982).Google Scholar
  15. 15.
    C. K. Law, “A simplified theoretical model for vapor-phase combustion of metal particles,” Combust. Sci. Technol., 7, 197–212 (1973).Google Scholar
  16. 16.
    A. Ulas, K. K. Kuo, and C. Gotzmer, “Ignition and combustion of boron particles in fluorine-containing environments,” Combust. Flame, 12, 1935–1957 (2001).Google Scholar
  17. 17.
    D. Meinköhn, “The ignition of boron particles,” Combust. Flame, 59, 225–232 (1985).Google Scholar
  18. 18.
    T. A. Brzustowski and I. Glassman, “Vapor-phase diffusion flames in the combustion of magnesium and aluminum,” in: H. G. Wolfhard et al. (eds.), Progress in Astronautic and Aeronautics, Vol. 15: Heterogeneous Combustion (1964), pp. 117–158.Google Scholar
  19. 19.
    M. Salita, “Deficiencies and requirements in modeling of slag generation in solid rocket motors,” J. Propuls. Power, 11, 10–23 (1995).Google Scholar
  20. 20.
    J. Happel and H. Brenner, Low Reynolds Number Hydrodynamics, Leyden, Noordhoff (1973).Google Scholar
  21. 21.
    J. P. Burelbach, S. C. Bankoff, and S. H. Davis, “Nonlinear stability of evaporating/condensing liquid films,” J. Fluid Mech., 195, 463–499 (1988).ADSGoogle Scholar
  22. 22.
    E. E. Shpilrain, K. A. Yakimovich, and A. F. Tsitsarkin, “Surface tension of liquid boric oxide at up to 2100°C,” High Temperature (USSR), 12, 77–82 (1974).Google Scholar
  23. 23.
    M. K. King, “A review of studies of boron ignition and combustion phenomena at Atlantic Research Corporation over the past decade,” in: K. K. Kuo and R. Pein (eds.), Proc. 2nd Int. Symp. on Special Topics in Chemical Propulsion: Combustion of Boron-Based Solid Propellants and Solid Fuels (Boca Raton, 1993), CRC Press, pp. 1–80.Google Scholar
  24. 24.
    A. N. Zolotko, L. A. Klyachko, K. M. Kopeika, et al., “Critical ignition conditions for boron particles suspended in a gas,” Combust., Expl., Shock Waves, 13, No. 1, 31–35 (1977).CrossRefGoogle Scholar
  25. 25.
    A. I. Grigor’ev, I. D. Grigor’eva, and V. I. Sigimov, “Oxidation kinetics of boron,” Combust., Expl., Shock Waves, 12, No. 1, 44–46 (1976).Google Scholar
  26. 26.
    Gmelin, Gmelins Handbuch der Anorganischen Chemie, Boron Compounds, 1st Suppl. Vol. 1, Springer Verlag (1980).Google Scholar

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • D. Meinköhn
    • 1
  1. 1.German Aerospace Center DLRHardthausenGermany

Personalised recommendations