Fast subsonic combustion of gases in an inert porous medium with a smooth rise in the pressure in the wave

Lyamin, G. A.; Pinaev, A. V.

doi:10.1007/bf00749298

Cited by 16 publications

(11 citation statements)

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“…Pinaev & Lyamin [33] proposed that the high-velocity regime (they refer to it as the rapid compression regime) be characterized by a subsonic front velocity and a front peak pressure of greater than 1.1-1.2 times the initial pressure, corresponding to a front velocity of about 20 m s −1 . Lyamin & Pinaev [34,35] found that in very reactive mixtures, e.g. stoichiometric acetylene-oxygen and hydrogen-oxygen mixtures, flame propagation in the sound velocity regime was not observed, even in tests performed in sand with particle sizes in the range 0.6-1.2 mm.…”

Section: (C) Sound Velocity Regimementioning

confidence: 99%

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Explosion propagation in inert porous media

Ciccarelli

2012

Phil. Trans. R. Soc. A.

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Porous media are often used in flame arresters because of the high surface area to volume ratio that is required for flame quenching. However, if the flame is not quenched, the flow obstruction within the porous media can promote explosion escalation, which is a well-known phenomenon in obstacle-laden channels. There are many parallels between explosion propagation through porous media and obstacle-laden channels. In both cases, the obstructions play a duel role. On the one hand, the obstruction enhances explosion propagation through an early shear-driven turbulence production mechanism and then later by shock-flame interactions that occur from lead shock reflections. On the other hand, the presence of an obstruction can suppress explosion propagation through momentum and heat losses, which both impede the unburned gas flow and extract energy from the expanding combustion products. In obstacle-laden channels, there are well-defined propagation regimes that are easily distinguished by abrupt changes in velocity. In porous media, the propagation regimes are not as distinguishable. In porous media the entire flamefront is affected, and the effects of heat loss, turbulence and compressibility are smoothly blended over most of the propagation velocity range. At low subsonic propagation speeds, heat loss to the porous media dominates, whereas at higher supersonic speeds turbulence and compressibility are important. This blending of the important phenomena results in no clear transition in propagation mechanism that is characterized by an abrupt change in propagation velocity. This is especially true for propagation velocities above the speed of sound where many experiments performed with fuel-air mixtures show a smooth increase in the propagation velocity with mixture reactivity up to the theoretical detonation wave velocity.

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Section: (C) Sound Velocity Regimementioning

confidence: 99%

“…Steady-state flame velocity measured in hydrogen-air mixtures in a porous medium consisting of 2.6-3.6 mm steel balls as a function of initial pressure is provided in figure 6 [35]. Also plotted on the graph is the measured speed of sound through the porous medium.…”

Section: (C) Sound Velocity Regimementioning

confidence: 99%

Explosion propagation in inert porous media

Ciccarelli

2012

Phil. Trans. R. Soc. A.

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“…Perhaps the physically simplest and yet experimentally feasible system for studying subsonic detonation is combustion in inert porous medium [32]. In this case, on the one hand, the distortions introduced by the porous matrix may be ignored while, on the other hand, the resistance of the matrix to the gas flow is often so strong that one may neglect the inertial effects and take Darcy's law as the momentum equation.…”

Section: Subsonic Detonation Mathematical Model and Major Physical Ementioning

confidence: 99%

“…However, the coupling between the two is not inevitable. In hydrodynamically resistant flows, as those which develop in porous beds, the burning velocity may fall significantly below its thermodynamic, Chapman Jouguet (CJ), value, and under certain conditions, the propagation may well become subsonic and therefore shockless [32], [33], [37], [39]. The shockless propagation still involves pressure peaks and is sustained by adiabatic compression which is now spread by the drag-induced diffusion of pressure.…”

Section: Introductionmentioning

confidence: 99%

Recent Mathematical Results on Combustion in Hydraulically Resistant Porous Media

Gordon

2007

Math. Model. Nat. Phenom.

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Abstract. Gaseous detonation is a phenomenon with very complicated dynamics which has been studied extensively by physicists, mathematicians and engineers for many years. Despite many efforts the problem is far from a complete resolution. Recently the theory of subsonic detonation that occurs in highly resistant porous media was proposed in [4]. This theory provides a model which is realistic, rich and suitable for a mathematical study. In particular, the model is capable of describing the transition from a slowly propagating deflagration wave to the fast detonation wave. This phenomena is known as a deflagration to detonation transition and is one of the most challenging issues in combustion theory. In this paper we will present some recent mathematical results concerning initiation of reaction in porous media, existence and uniqueness of traveling fronts, quenching and propagation.

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“…Perhaps the physically simplest and yet experimentally quite feasible system for studying subsonic detonation is combustion in an inert porous medium [2]. In this case, on the one hand, the distortions introduced by the porous matrix may be ignored while, on the other hand, the resistance of the matrix to the gas flow is often so strong that one may neglect the inertial effects and take Darcy's law as the momentum equation.…”

Section: Introductionmentioning

confidence: 99%

On metastable deflagration in porous medium combustion

Bessonov

Gordon

Sivashinsky

et al. 2005

Applied Mathematics Letters

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A regime of low velocity deflagration in hydraulically resisted flows such as those occurring in porous beds is discussed. An asymptotic expression for the deflagration velocity is derived. The obtained dependency elucidates the mechanism controlling the gradual enhancement of the propagation velocity prior to the abrupt transition from slow to fast combustion. This enhancement is caused by the drag-induced diffusion of pressure ahead of the advancing front. The time of transition from the slow to fast propagation is estimated.

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Fast subsonic combustion of gases in an inert porous medium with a smooth rise in the pressure in the wave

Cited by 16 publications

References 1 publication

Explosion propagation in inert porous media

Explosion propagation in inert porous media

Recent Mathematical Results on Combustion in Hydraulically Resistant Porous Media

On metastable deflagration in porous medium combustion

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