Detonation

For detonation in spark-ignition engines, see Engine knocking.
Not to be confused with Denotation.
Detonation of TNT, and shock wave

Detonation (from Latin detonare 'to thunder down/forth')[1] is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with speeds about 1 km/sec and differ from deflagrations which have subsonic flame speeds about 1 m/sec.[2] Detonation is an explosion of fuel-air mixture. Compared to deflagration, detonation doesn't need to have an external oxidizer. Oxidizers and fuel mix when deflagration occurs. Detonation is more destructive than deflagrations. In detonation, the flame front travels through the air-fuel faster than sound; while in deflagration, the flame front travels through the air-fuel slower than sound.

Detonations occur in both conventional solid and liquid explosives,[3] as well as in reactive gases. TNT, dynamite, and C4 are examples of high power explosives that detonate. The velocity of detonation in solid and liquid explosives is much higher than that in gaseous ones, which allows the wave system to be observed with greater detail (higher resolution).

A very wide variety of fuels may occur as gases (e.g. hydrogen), droplet fogs, or dust suspensions. In addition to dioxygen, oxidants can include halogen compounds, ozone, hydrogen peroxide, and oxides of nitrogen. Gaseous detonations are often associated with a mixture of fuel and oxidant in a composition somewhat below conventional flammability ratios. They happen most often in confined systems, but they sometimes occur in large vapor clouds. Other materials, such as acetylene, ozone, and hydrogen peroxide, are detonable in the absence of an oxidant (or reductant). In these cases the energy released results from the rearrangement of the molecular constituents of the material.[4][5]

Detonation was discovered in 1881 by four French scientists Marcellin Berthelot and Paul Marie Eugène Vieille[6] and Ernest-François Mallard and Henry Louis Le Chatelier.[7] The mathematical predictions of propagation were carried out first by David Chapman in 1899[8] and by Émile Jouguet in 1905,[9] 1906 and 1917.[10] The next advance in understanding detonation was made by John von Neumann[11] and Werner Döring[12] in the early 1940s and Yakov B. Zel'dovich and Aleksandr Solomonovich Kompaneets in the 1960s.[13]

  1. ^ Oxford Living Dictionaries. "detonate". British & World English. Oxford University Press. Archived from the original on February 22, 2019. Retrieved 21 February 2019.
  2. ^ Handbook of Fire Protection Engineering (5 ed.). Society of Fire Protection Engineers. 2016. p. 390.
  3. ^ Fickett, Wildon; Davis, William C. (1979). Detonation. University of California Press. ISBN 978-0-486-41456-0.
  4. ^ Stull, Daniel Richard (1977). Fundamentals of fire and explosion. Monograph Series. Vol. 10. American Institute of Chemical Engineers. p. 73. ISBN 978-0-816903-91-7.
  5. ^ Urben, Peter; Bretherick, Leslie (2006). Bretherick's Handbook of Reactive Chemical Hazards (7th ed.). London: Butterworths. ISBN 978-0-123725-63-9.
  6. ^ Berthelot, Marcellin; and Vieille, Paul Marie Eugène; « Sur la vitesse de propagation des phénomènes explosifs dans les gaz » ["On the velocity of propagation of explosive processes in gases"], Comptes rendus hebdomadaires des séances de l'Académie des sciences, vol. 93, pp. 18–22, 1881
  7. ^ Mallard, Ernest-François; and Le Chatelier, Henry Louis; « Sur les vitesses de propagation de l’inflammation dans les mélanges gazeux explosifs » ["On the propagation velocity of burning in gaseous explosive mixtures"], Comptes rendus hebdomadaires des séances de l'Académie des sciences, vol. 93, pp. 145–148, 1881
  8. ^ Chapman, David Leonard (1899). "VI. On the rate of explosion in gases", The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 47(284), 90-104.
  9. ^ Cite error: The named reference Jouguet1905 was invoked but never defined (see the help page).
  10. ^ Jouguet, Jacques Charles Émile (1917). L'Œuvre scientifique de Pierre Duhem, Doin.
  11. ^ Cite error: The named reference vonNeumann was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Döring was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Zel'dovichKompaneets was invoked but never defined (see the help page).