This model admits finite-rate chemical reactions and thus the process of detonation consists of the following stages. First, an infinitesimally thin shock wave compresses the explosive to a high pressure called the von Neumann spike. At the von Neumann spike point the explosive still remains unreacted. The spike marks the onset of the zone of exothermic chemical reaction, which finishes at the Chapman–Jouguet state. After that, the detonation products expand backward.
In the reference frame in which the shock is stationary, the flow following the shock is subsonic. Because of this, energy release behind the shock is able to be transported acoustically to the shock for its support. For a self-propagating detonation, the shock relaxes to a speed given by the Chapman–Jouguet condition, which induces the material at the end of the reaction zone to have a locally sonic speed in the reference frame in which the shock is stationary. In effect, all of the chemical energy is harnessed to propagate the shock wave forward.
However, in the 1960s, experiments revealed that gas-phase detonations were most often characterized by unsteady, three-dimensional structures, which can only in an averaged sense be predicted by one-dimensional steady theories. Indeed, such waves are quenched as their structure is destroyed.[4][5] The Wood–Kirkwood detonation theory can correct for some of these limitations.[6]
Referencesedit
^Zel’dovich, Ya. B. (1940). "On the theory of the propagation of detonation in gaseous systems" К теории распространения детонации в газообразных системах [On the theory of the propagation of detonations on gaseous system]. Zhurnal Éksperimental'noĭ i Teoreticheskoĭ Fiziki (in Russian). 10: 542–568. hdl:2060/19930093969. English translation.
^von Neumann, J. (1963) [1942]. "Theory of detonation waves. Progress Report to the National Defense Research Committee Div. B, OSRD-549 (PB 31090)". In Taub, A. H. (ed.). John von Neumann: Collected Works, 1903–1957. Vol. 6. New York: Pergamon Press. pp. 178–218. ISBN978-0-08-009566-0.
^Döring, W. (1943). "Über Detonationsvorgang in Gasen" [On detonation processes in gases]. Annalen der Physik (in German). 43 (6–7): 421–436. Bibcode:1943AnP...435..421D. doi:10.1002/andp.19434350605. ISSN 0003-4916.
^Edwards, D. H.; Thomas, G. O.; Nettleton, M. A. (1979). "The Diffraction of a Planar Detonation Wave at an Abrupt Area Change". Journal of Fluid Mechanics. 95 (1): 79–96. Bibcode:1979JFM....95...79E. doi:10.1017/S002211207900135X. S2CID 123018814.
^Edwards, D. H.; Thomas, G. O.; Nettleton, M. A. (1981). A. K. Oppenheim; N. Manson; R. I. Soloukhin; J. R. Bowen (eds.). Diffraction of a Planar Detonation in Various Fuel-Oxygen Mixtures at an Area Change. Progress in Astronautics & Aeronautics. Vol. 75. p. 341. doi:10.2514/5.9781600865497.0341.0357. ISBN978-0-915928-46-0.
^Glaesemann, Kurt R.; Fried, Laurence E. (2007). "Improved wood–kirkwood detonation chemical kinetics". Theoretical Chemistry Accounts. 120 (1–3): 37–43. doi:10.1007/s00214-007-0303-9. S2CID 95326309.
detonation, model, dimensional, model, process, detonation, explosive, proposed, during, world, independently, dovich, john, neumann, werner, döring, hence, name, this, model, admits, finite, rate, chemical, reactions, thus, process, detonation, consists, foll. The ZND detonation model is a one dimensional model for the process of detonation of an explosive It was proposed during World War II independently by Y B Zel dovich 1 John von Neumann 2 and Werner Doring 3 hence the name This model admits finite rate chemical reactions and thus the process of detonation consists of the following stages First an infinitesimally thin shock wave compresses the explosive to a high pressure called the von Neumann spike At the von Neumann spike point the explosive still remains unreacted The spike marks the onset of the zone of exothermic chemical reaction which finishes at the Chapman Jouguet state After that the detonation products expand backward In the reference frame in which the shock is stationary the flow following the shock is subsonic Because of this energy release behind the shock is able to be transported acoustically to the shock for its support For a self propagating detonation the shock relaxes to a speed given by the Chapman Jouguet condition which induces the material at the end of the reaction zone to have a locally sonic speed in the reference frame in which the shock is stationary In effect all of the chemical energy is harnessed to propagate the shock wave forward However in the 1960s experiments revealed that gas phase detonations were most often characterized by unsteady three dimensional structures which can only in an averaged sense be predicted by one dimensional steady theories Indeed such waves are quenched as their structure is destroyed 4 5 The Wood Kirkwood detonation theory can correct for some of these limitations 6 References edit Zel dovich Ya B 1940 On the theory of the propagation of detonation in gaseous systems K teorii rasprostraneniya detonacii v gazoobraznyh sistemah On the theory of the propagation of detonations on gaseous system Zhurnal Eksperimental noĭ i Teoreticheskoĭ Fiziki in Russian 10 542 568 hdl 2060 19930093969 English translation von Neumann J 1963 1942 Theory of detonation waves Progress Report to the National Defense Research Committee Div B OSRD 549 PB 31090 In Taub A H ed John von Neumann Collected Works 1903 1957 Vol 6 New York Pergamon Press pp 178 218 ISBN 978 0 08 009566 0 Doring W 1943 Uber Detonationsvorgang in Gasen On detonation processes in gases Annalen der Physik in German 43 6 7 421 436 Bibcode 1943AnP 435 421D doi 10 1002 andp 19434350605 ISSN 0003 4916 Edwards D H Thomas G O Nettleton M A 1979 The Diffraction of a Planar Detonation Wave at an Abrupt Area Change Journal of Fluid Mechanics 95 1 79 96 Bibcode 1979JFM 95 79E doi 10 1017 S002211207900135X S2CID 123018814 Edwards D H Thomas G O Nettleton M A 1981 A K Oppenheim N Manson R I Soloukhin J R Bowen eds Diffraction of a Planar Detonation in Various Fuel Oxygen Mixtures at an Area Change Progress in Astronautics amp Aeronautics Vol 75 p 341 doi 10 2514 5 9781600865497 0341 0357 ISBN 978 0 915928 46 0 Glaesemann Kurt R Fried Laurence E 2007 Improved wood kirkwood detonation chemical kinetics Theoretical Chemistry Accounts 120 1 3 37 43 doi 10 1007 s00214 007 0303 9 S2CID 95326309 Further reading editDremin Anatoliĭ Nikolaevich 1999 Toward Detonation Theory Springer ISBN 978 0 387 98672 2 Retrieved from https en wikipedia org w index php title ZND detonation model amp oldid 1146017333, wikipedia, wiki, book, books, library,
