Some open issues in premixed turbulent combustion

Ronney, Paul D.

doi:10.1007/3-540-59224-5_1

Cited by 62 publications

(79 citation statements)

References 51 publications

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“…By fixing θ = 1 for x → −∞ and θ = 0 for x → ∞ the front propagates from left to right. It is natural to expect that the front speed can be expressed according to the following relation [7,25,26] …”

Section: Stationary Cellular Flowmentioning

confidence: 99%

Thin front propagation in steady and unsteady cellular flows

et al. 2003

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Front propagation in two dimensional steady and unsteady cellular flows is investigated in the limit of very fast reaction and sharp front, i.e., in the geometrical optics limit. In the steady case, by means of a simplified model, we provide an analytical approximation for the front speed, v f , as a function of the stirring intensity, U , in good agreement with the numerical results and, for large U , the behavior v f ∼ U/ log(U ) is predicted. The large scale of the velocity field mainly rules the front speed behavior even in the presence of smaller scales. In the unsteady (time-periodic) case, the front speed displays a phase-locking on the flow frequency and, albeit the Lagrangian dynamics is chaotic, chaos in front dynamics only survives for a transient. Asymptotically the front evolves periodically and chaos manifests only in the spatially wrinkled structure of the front.

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Section: Stationary Cellular Flowmentioning

confidence: 99%

Thin front propagation in steady and unsteady cellular flows

et al. 2003

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“…Therefore, in the following, we consider the velocity field as given. This approximation, hardly tenable in the context of flame propagation in gases, is rather appropriate for chemical front propagation in some liquid solutions [2,[5][6][7]. Under these simplifying assumptions, the evolution of θ is described by…”

Section: Introductionmentioning

confidence: 99%

Front speed enhancement in cellular flows

Abel

Cencini

Vergni

et al. 2002

Chaos: An Interdisciplinary Journal of Nonlinear Science

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The problem of front propagation in a stirred medium is addressed in the case of cellular flows in three different regimes: slow reaction, fast reaction and geometrical optics limit. It is well known that a consequence of stirring is the enhancement of front speed with respect to the non-stirred case. By means of numerical simulations and theoretical arguments we describe the behavior of front speed as a function of the stirring intensity, $U$. For slow reaction, the front propagates with a speed proportional to $U^{1/4}$, conversely for fast reaction the front speed is proportional to $U^{3/4}$. In the geometrical optics limit, the front speed asymptotically behaves as $U/\ln U$.Comment: 10 RevTeX pages, 10 included eps figure

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“…4 Mainly due to its practical relevance in combustion processes, the subject has motivated numerous theoretical as well as experimental efforts. [5][6][7][8][9][10] The generic understanding coming from these studies is that the turbulent front velocity v T is larger than v 0 , to an extent which depends on the intensity and spatiotemporal correlations of the turbulent flow. Some other issues, however, such as velocity quenching effects, role of turbulent spectra remain somewhat more open.…”

Section: Introductionmentioning

confidence: 99%

Front dynamics in turbulent media

1997

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A study of a stable front propagating in a turbulent medium is presented. The front is generated through a reaction-diffusion equation, and the turbulent medium is statistically modeled using a Langevin equation. Numerical simulations indicate the presence of two different dynamical regimes. These regimes appear when the turbulent flow either wrinkles a still rather sharp propagating interfase or broadens it. Specific dependences of the propagating velocities on stirring intensities appropriate to each case are found and fitted when possible according to theoretically predicted laws. Different turbulent spectra are considered.

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Some open issues in premixed turbulent combustion

Cited by 62 publications

References 51 publications

Thin front propagation in steady and unsteady cellular flows

Thin front propagation in steady and unsteady cellular flows

Front speed enhancement in cellular flows

Front dynamics in turbulent media

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