Some observations on the initiation and onset of detonation

Thomas, G.O.

doi:10.1098/rsta.2011.0368

Cited by 26 publications

(13 citation statements)

References 62 publications

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“…If shock preheating occurs in phase with the reaction wave a detonation is formed [20]. This behaviour is typical of deflagration-to-detonation transition (DDT) processes [33][34][35][36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

Acoustic timescale characterisation of symmetric and asymmetric multidimensional hot spots

Kurtz

Regele

2014

Combustion Theory and Modelling

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In this work, two-dimensional hot spots are modelled by combining a linear temperature gradient with a constant temperature plateau. This approach retains the simplicity of a linear temperature gradient, but captures the effects of a local temperature maximum of finite size. Symmetric and asymmetric plateau regions are modelled using both rectangular and elliptical geometries. A one-step Arrhenius reaction for H 2 -air is used to model the reactive mixture. Plateaus with different ratios of excitation to acoustic timescales, spanning two orders of magnitude, are simulated. Even with clear differences in behaviour between one and two dimensions, the a priori prescribed hot spot timescale ratio is shown to characterise the 2-D gasdynamic response. The relationship between one and two dimensions is explored using asymmetric plateau regions. It is shown that 1-D behaviour is recovered over a finite time. Furthermore, the duration of this 1-D behaviour is directly related to the asymmetry of the plateau.

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Section: Introductionmentioning

confidence: 99%

Acoustic timescale characterisation of symmetric and asymmetric multidimensional hot spots

Kurtz

Regele

2014

Combustion Theory and Modelling

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“…Although warranted, an extensive review of this topic is beyond the scope of the current discussion. The interested reader is again referred to the paper in this Issue by Thomas [1] and references therein. For detonations propagating through large enough systems, the properties of the cellular structures are now believed to be independent of boundary conditions and can be considered a property of the kinetics of energy release for a particular gas mixture.…”

Section: Introductionmentioning

confidence: 99%

“…The points of intersection of these waves are called triple shock configurations or, more commonly, triple points. Many detailed descriptions of the structure of triple points exist in the literature (see the paper by Thomas [1] in this Issue and references therein for more details); so here we introduce only the most basic concepts relevant to our topic of interest. Examples of the pressure distribution in the vicinity of the reaction front of a simulated planar *Author for correspondence (dakessle@lcp.nrl.navy.mil).…”

Section: Introductionmentioning

confidence: 99%

Gas-phase detonation propagation in mixture composition gradients

Kessler

Gamezo

Oran

2012

Phil. Trans. R. Soc. A.

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The propagation of detonations through several fuel-air mixtures with spatially varying fuel concentrations is examined numerically. The detonations propagate through twodimensional channels, inside of which the gradient of mixture composition is oriented normal to the direction of propagation. The simulations are performed using a twocomponent, single-step reaction model calibrated so that one-dimensional detonation properties of model low-and high-activation-energy mixtures are similar to those observed in a typical hydrocarbon-air mixture. In the low-activation-energy mixture, the reaction zone structure is complex, consisting of curved fuel-lean and fuel-rich detonations near the line of stoichiometry that transition to decoupled shocks and turbulent deflagrations near the channel walls where the mixture is extremely fuellean or fuel-rich. Reactants that are not consumed by the leading detonation combine downstream and burn in a diffusion flame. Detonation cells produced by the unstable reaction front vary in size across the channel, growing larger away from the line of stoichiometry. As the size of the channel decreases relative to the size of a detonation cell, the effect of the mixture composition gradient is lessened and cells of similar sizes form. In the high-activation-energy mixture, detonations propagate more slowly as the magnitude of the mixture composition gradient is increased and can be quenched in a large enough gradient.

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“…The DDT of a compound is a process of accelerating the reaction by having the propagation mechanism transition from thermal to shock wave driven [5,[28][29][30][31]. This process is complex and can come about by high energy shock wave, a mix of shock wave and thermal energy or very high temperature gradients [26,[32][33][34][35]. This is an advantageous process as only small amounts of primary explosives are needed to induce DDT of a propellant or pyrolant.…”

Section: Primersmentioning

confidence: 99%

Towards Safer Primers: A Review

Lundgaard

Cahill

et al. 2019

Technologies

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Primers are used to reliably initiate a secondary explosive in a wide range of industrial and defence applications. However, established primer technologies pose both direct and indirect risks to health and safety. This review analyses a new generation of primer materials and ignition control mechanisms that have been developed to address these risks in firearms. Electrically or optically initiated metal, oxide and semiconductor-based devices show promise as alternatives for heavy metal percussive primers. The prospects for wider use of low-cost, safe, reliable and non-toxic primers are discussed in view of these developments.

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Some observations on the initiation and onset of detonation

Cited by 26 publications

References 62 publications

Acoustic timescale characterisation of symmetric and asymmetric multidimensional hot spots

Acoustic timescale characterisation of symmetric and asymmetric multidimensional hot spots

Gas-phase detonation propagation in mixture composition gradients

Towards Safer Primers: A Review

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