Detonation waves in gaseous reactive mixtures have been known to exhibit multidimensional structure since the 1950's. The interaction of shocks and presence of unsteady triple shock interactions in the detonation structure give rise to the detonation cell, the size of which is determined by the reactive mixture and initial conditions. Detonable gaseous mixtures have been classified as regular or irregular, depending on their behavior in particular experimental conditions. The main combustion mechanisms in the structure of irregular mixtures have not yet been positively identified. The structure of detonation waves in an irregular mixture of stoichiometric methane and oxygen is observed using non-intrusive visual diagnostics. Framing schlieren, streak schlieren and framing self-luminous imaging were used, yielding, respectively, an instantaneous measure of the density gradient, a time evolution of the density gradients and a record of the regions of high luminosity. Regions of high luminosity correspond qualitatively to regions of high chemical reaction. Pockets of high density gas were observed behind the lead shock surface. Light emission was observed, using framing self-luminous imaging, at the edges of these pockets indicating the pockets burned primarily at the edges. The amount of mass burned in one such pocket was found to be 40% of the total mass burned in one cell cycle. The induction time of a particle undergoing shock compression was calculated. The cases of constant properties behind the shock and of a decaying blast followed by expansion waves were considered as characteristic induction times of shock-induced combustion. Both measures of induction time were found to be longer than the typical time scale of a particle burning in one of the observed pockets. Furthermore, the coincidence of light emission with the edges of the pocket of unburned gas and the long time scales involved indicate the burning mechanism of this unburned pocket to be turbulent diffusion rather than shock compression.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.98981 |
| Date | January 2005 |
| Creators | Kiyanda, Charles Basenga. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Mechanical Engineering.) |
| Rights | © Charles Basenga Kiyanda, 2005 |
| Relation | alephsysno: 002338145, proquestno: AAIMR24978, Theses scanned by UMI/ProQuest. |
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