Journal ArticleDOI
Dynamic Parameters of Gaseous Detonations
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In this paper, the authors considered homogeneous gaseous fuel-air detonations and showed that the propagation of the combustion wave is governed by the molecular diffusion of heat and mass from the reaction zone to the unburned mixture, and that the very strong exponential temperature dependence of chemical reaction rates makes possible the rapid combustion in the detonation mode.Abstract:
In addition to gases, flammable liquids and solids in the form of fine droplets and dust particles also form explosive mixtures with air. An explosive mixture can, in general, support two modes of combustion. The slow laminar deflagration mode is at one extreme; here the flame propagates at typical velocities of the order 1 m s -1 relative to the unburned gases and there is negligible overpressure development when the explosion is unconfined. At the other extreme is the detonation mode, in which the detonation wave propagates at about 2000 m s -1 accompanied by an overpressure rise of about 20 bars across the wave. The propagation of laminar defiagrations is governed by the molecular diffusion of heat and mass from the reaction zone to the unburned mixture. The propagation of detonations depends on the adiabatic shock compression of the unburned mixtures to elevated temperatures to bring about autoignition. The very strong exponential temperature dependence of chemical reaction rates in general makes possible the rapid combustion in the detonation mode. Two phase liquid droplets or dust-air mixtures are similar, but they require more physical processes (e.g. droplet break-up, phase change, mixing, etc.) prior to combustion. Thus, characteristic time or length scales associated with the combustion front are usually much larger than those of homogeneous gaseous fuel-air mixtures. The essential mechanisms of propagation of the combustion waves, however, are similar. In between the two extremes of laminar detlagration and detonation, there is an almost continuous spectrum of burning rates where turbulence plays the dominant role in the combustion process. Due to space limitations, only homogeneous gaseous fuel-air detonations are considered in this article.read more
Citations
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Proceedings ArticleDOI
Computation of dynamic parameters of detonation in hydrogen-air and propane-air mixtures using detailed chemistry
Journal ArticleDOI
Numerical Investigation of the Oblique Detonation Waves and Stability in a Super-Detonative Ram Accelerator
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Journal ArticleDOI
Investigation of the dynamic properties of the cellular structure of a gas-detonation wave
O. V. Achasov,O. G. Penyazkov +1 more
TL;DR: In this article, the evolution of the cellular structure of a gas-detonation wave propagating in a circular pipe was investigated, and it was shown that the realization of only the single-mode regime of propagation is improbable and that the complete state of the wavefront structure as a function of time can be represented as a superposition of periodic functions corresponding to the states of neighboring detonation modes.
Book ChapterDOI
Structure of Unstable Gas Detonation Front
A. A. Borisov,O. V. Sharypov +1 more
TL;DR: In this article, the formation of a characteristic cellular structure of the unstable gas detonation front is considered, and it is shown that the surface of the front belongs to the class of dissipative structures known in many nonequilibrium open physical and chemical systems.
The effects of porous media on explosion development in partially filled enclosures
TL;DR: In this article, the authors present a literature review on the effects of flame acceleration in a tube and demonstrate the effect of flames on the normal reflection of a tube in a normal reflection image.
References
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Journal ArticleDOI
The mechans of transition from deflagration to detonation in vapor cloud explosions
J.H.S. Lee,I.O. Moen +1 more
Journal ArticleDOI
The critical tube diameter for detonation failure in hydrocarbon-air mixtures☆
TL;DR: In this paper, the critical tube diameters dc for the successful transformation of a planar to a spherical detonation have been measured in nine gaseous fuels (CH4, C2H2, C 2H4, c2H6, C3H8, C4H10, MAPP and H2) in stoichiometric fuel-oxygen mixtures diluted with nitrogen at atmospheric initial pressure.
Journal ArticleDOI
Chemical kinetics of hydrocarbon oxidation in gaseous detonations
TL;DR: In this article, a theoretical model including a detailed chemical kinetic reaction mechanism for hydrocarbon oxidation was used to examine detonation properties for mixtures of fuel, including methane, ethylene, acetylene, and methanol.
Journal ArticleDOI
On the measure of the relative detonation hazards of gaseous fuel-oxygen and air mixtures
Hidenori Matsui,John H.S. Lee +1 more
TL;DR: In this article, the critical energy for direct initiation of spherical detonation for eight gaseous fuels (C 2 H 2, C 2 H 4 O, C 2 HO 4 O, C 3 H 6, C 1 H 8, CH 4 and H 2 ) have been measured using a planar detonation from a linear tube for initiation.