Effect of Lewis number on flame front fragmentation in narrow closed channels

Karlin, Vladimir; Makhviladze, G. M.; Roberts, J.P.; Мелихов, В. И.

doi:10.1016/s0010-2180(99)00083-8

Cited by 12 publications

(4 citation statements)

References 27 publications

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“…Furthermore to avoid the problems with the inflow/outflow boundary condition one also could consider flames in closed tubes such that these boundaries also have physical no-slip wall conditions (e.g. as in Karlin et al 2000), and study the dependence on the tube lengths. We hence also intend to investigate these types of tube/channel problems in the future.…”

Section: Discussionmentioning

confidence: 99%

Nonlinear cellular instabilities of planar premixed flames: numerical simulations of the Reactive Navier–Stokes equations

Sharpe

Falle

2006

Combustion Theory and Modelling

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Abstract. Two-dimensional compressible Reactive Navier-Stokes numerical simulations of intrinsic planar, premixed flame instabilities are performed. The initial growth of a sinusoidally perturbed planar flame is first compared with the predictions of a recent exact linear stability analysis, and it is shown the analysis provides a necessary but not sufficient test problem for validating numerical schemes intended for flame simulations. The long-time nonlinear evolution up to the final nonlinear stationary cellular flame is then examined for numerical domains of increasing width. It is shown that for routinely computationally affordable domain widths, the evolution and final state is, in general, entirely dependent on the width of the domain and choice of numerical boundary conditions. It is also shown that the linear analysis has no relevance to the final nonlinear cell size. When both hydrodynamic and thermal-diffusive effects are important, the evolution consists of a number of symmetry breaking cell splitting and re-merging processes which results in a stationary state of a single very asymmetric cell in the domain, a flame shape which is not predicted by weakly nonlinear evolution equations. Resolution studies are performed and it is found that lower numerical resolutions, typical of those used in previous works, do not give even the qualitatively correct solution in wide domains. We also show that the long-time evolution, including whether or not a stationary state is ever achieved, depends on the choice of the numerical boundary conditions at the inflow and outflow boundaries, and on the numerical domain length and flame Mach number for the types of boundary conditions used in some previous works.

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Section: Discussionmentioning

confidence: 99%

Nonlinear cellular instabilities of planar premixed flames: numerical simulations of the Reactive Navier–Stokes equations

Sharpe

Falle

2006

Combustion Theory and Modelling

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“…consideration of small Lewis numbers, see e.g. [26], could fix the problem too. Table 1 in [24] shows that the range of flame wrinkles, in terms of the semi-apex fold angle α, able to generate a detonation, widens as heat conductivity, represented by thermal diffusivity , grows.…”

Section: Numerical Experimentsmentioning

confidence: 99%

Radiation Preheating can Trigger Transition from Deflagration to Detonation

Karlin¹

2010

Flow Turbulence Combust

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In this article the possibility of radiation heat transfer to trigger transition to detonation is studied. It is assumed that the premixed deflagration front is able to emit and the unburnt mixture to absorb radiation heat effectively. Under this assumption the ability of the flame to significantly preheat the unburnt mixture and to form a promoting temperature gradient is investigated. First, we estimate the temperature rise due to the radiation preheating of the unburnt mixture, when it is traveling through deep flame wrinkles. Subsequently, we carry out numerical simulations of premixed gaseous combustion in a tube. The simulations confirm the possibility of formation of promoting temperature gradients within flame folds and initiation of the detonation waves. They demonstrate the plausibility of the proposed mechanism of the deflagration to detonation transition.

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“…The flame front during propagating event exhibits various shapes such as curved, flat, cusped or cellular fronts [1]- [3]. This is due to the various types of causes such as Lewis number effect, flame-flow interaction, body-force effect, flame front-acoustic wave interaction and so on [4]- [7]. These flames are often transient rather than long-lasting, therefore, we refer their motion as "instability".…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of an In-line Pre-Heating Treatment along the Axis on the Propagation of a Laminar Premixed Flame in a Channel

Hossain

Oshima

Nakamura

et al. 2009

JTST

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In this study, an in-line pre-heating effect on the propagation of a laminar premixed flame in a two-dimensional channel is investigated numerically. An in-line pre-heating thickness of 1mm is generated by imposing uniform external high-temperature along the center line in the prescribed channel. It is found that the shapes of flame and propagation speeds are strongly affected by the pre-heating effect. The distribution of velocity pointed to ahead of the propagating flame (called negative velocity hereafter) is clearly observed which is susceptible to the generation of the pair of vortex in ahead of the flame tip. The evolution of negative flow field in front of premixed flame is successfully captured first ever in a time-dependent manner. The obtained flame propagation accompanied with the aforementioned negative velocity field is not only useful to elucidate the laser induced flame instability reported recently by Tsuchimoto et al. (2007), but also to consider the pure thermal effect on flame evolution, which is hard to obtain experimentally.

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Effect of Lewis number on flame front fragmentation in narrow closed channels

Cited by 12 publications

References 27 publications

Nonlinear cellular instabilities of planar premixed flames: numerical simulations of the Reactive Navier–Stokes equations

Nonlinear cellular instabilities of planar premixed flames: numerical simulations of the Reactive Navier–Stokes equations

Radiation Preheating can Trigger Transition from Deflagration to Detonation

Numerical Study of an In-line Pre-Heating Treatment along the Axis on the Propagation of a Laminar Premixed Flame in a Channel

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