Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical...
Transcript of Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical...
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Some observations on the initiation and onset of detonation
by Geraint Thomas
Philosophical Transactions AVolume 370(1960):715-739
February 13, 2012
©2012 by The Royal Society
![Page 2: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/2.jpg)
Spark schlieren images of (a) a turbulent flame and (b) a detonation.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 3: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/3.jpg)
Predicted cell widths (open squares) and peak measured wavefront pressure (filled circles) versus nitrogen dilution in (a) ethylene–oxygen and (b) silane-nitrous oxide.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 4: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/4.jpg)
(a) Smoked foil and (b) sketch of direct initiation of a hemispherical detonation.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 5: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/5.jpg)
(a) Smoked foil of direct initiation of a cylindrical detonation.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 6: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/6.jpg)
(a) Streak schlieren image and (b) sketch of key features observed during the direct planar shock initiation of a detonation.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 7: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/7.jpg)
Pressure records showing the temporal evolution of pressure at a number of gauge locations in a 30 m long, 0.15 m diameter pipe filled with: (a) ethylene in air and (b) hydrogen in air.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 8: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/8.jpg)
Spark schlieren images of detonation diffraction from a rectangular channel: (a) subcritical transmission, (b) critical transmission and (c) supercritical transmission.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 9: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/9.jpg)
Numerical simulations of a diffracting detonation.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 10: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/10.jpg)
Sequence of schlieren images showing the initial distortion of the flame bubble by an incident shock (mixture C2H4+3O2+4N2, incident shock Mach number 1.7, frame interval 50 μs).
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 11: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/11.jpg)
Sequence of schlieren images of shock–flame interactions for an incident shock Mach number of 2.5, mixture composition C2H4+3O2+4N2, frame interval of 10 μs.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 12: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/12.jpg)
Spark schlieren images showing the emergence of detonation in reflected shock region, gas mixture C2H4+3O2+12 Ar.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 13: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/13.jpg)
Numerical simulation output showing development of conditions conducive to onset of detonation following turbulent flame acceleration in a long pipe, open at one end.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society
![Page 14: Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012.](https://reader030.fdocuments.in/reader030/viewer/2022032415/56649f065503460f94c1baa2/html5/thumbnails/14.jpg)
Sketch illustrating different modes of high and low source energy and associated key blast or flame-acceleration processes that can lead to detonation in a reactive medium.
Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739
©2012 by The Royal Society