Propagation velocities of chemical reaction fronts advected by Poiseuille flow

Edwards, Boyd F.

doi:10.1063/1.2358954

“…In contrast to flame propagation in combustion, 4 where it has been analyzed thoroughly theoretically and experimentally, the effect of fluid flow (laminar or turbulent) on reaction fronts has not been explored in detail until recently. [18][19][20][21][22][23][24] In these papers, the steady flow is unidir-ectional (same direction as the chemical wave front) and is either a parabolic Poiseuille flow between two parallel solid boundaries or an unbounded spatial sinusoidal flows. The term "supportive" stands for the flow and the chemical reaction front (without flow) propagating in the same direction, and "adverse" when they are in opposite directions.…”

Section: Introductionmentioning

confidence: 99%

CHEMO-hydrodynamic coupling between forced advection in porous media and self-sustained chemical waves

Atis

¹

,

Saha

²

,

Auradou

³

et al. 2012

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Autocatalytic reaction fronts between two reacting species in the absence of fluid flow, propagate as solitary waves. The coupling between autocatalytic reaction front and forced simple hydrodynamic flows leads to stationary fronts whose velocity and shape depend on the underlying flow field. We address the issue of the chemico-hydrodynamic coupling between forced advection in porous media and self-sustained chemical waves. Towards that purpose, we perform experiments over a wide range of flow velocities with the well characterized iodate arsenious acid and chlorite-tetrathionate autocatalytic reactions in transparent packed beads porous media. The characteristics of these porous media such as their porosity, tortuosity, and hydrodynamics dispersion are determined. In a pack of beads, the characteristic pore size and the velocity field correlation length are of the order of the bead size. In order to address these two length scales separately, we perform lattice Boltzmann numerical simulations in a stochastic porous medium, which takes into account the log-normal permeability distribution and the spatial correlation of the permeability field. In both experiments and numerical simulations, we observe stationary fronts propagating at a constant velocity with an almost constant front width. Experiments without flow in packed bead porous media with different bead sizes show that the front propagation depends on the tortuous nature of diffusion in the pore space. We observe microscopic effects when the pores are of the size of the chemical front width. We address both supportive co-current and adverse flows with respect to the direction of propagation of the chemical reaction. For supportive flows, experiments and simulations allow observation of two flow regimes. For adverse flow, we observe upstream and downstream front motion as well as static front behaviors over a wide range of flow rates. In order to understand better these observed static state fronts, flow experiments around a single obstacle were used to delineate the range of steady state behavior. A model using the "eikonal thin front limit" explains the observed steady states.

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“…First, we delineate the Taylor regime in the case of a stationary Poiseuille profile. 18,20 Then, we extend the results to the quasistatic regime of an oscillating flow.…”

Section: Introductionmentioning

confidence: 92%

“…[16][17][18]20 To address Taylor's mixing regime in slowly oscillating flows, we will recall first the main expressions obtained for stationary flows in the frame of Taylor's description and study their range of validity in the case of a Poiseuille flow.…”

Section: Study Of the Low Frequency Taylor's Regimementioning

confidence: 99%

“…Note that for intermediate values of , an analytical fit of the front velocity has been recently proposed. 20 The main idea of the present paper is to address the effect of a pulsating flow on the front propagation. Recently, Nolen and Xin 12 studied the effect of a time and space periodic flow on the front propagation velocity from a numerical and analytical point of view.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Taylor’s regime of an autocatalytic reaction front in a pulsative periodic flow

Leconte

¹

,

Jarrige

²

,

Martin

³

et al. 2008

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Autocatalytic reaction fronts between reacted and unreacted species may propagate as solitary waves, that is, at a constant front velocity and with a stationary concentration profile, which result from a balance between molecular diffusion and chemical reaction. A velocity field in the supporting medium may affect the propagation of such fronts through different phenomena: advection, diffusion enhancement, front shape changes, etc. Here, we report on an experimental study and lattice Bhatnagar-Gross-Krook numerical simulations of the effect of an oscillating flow on the autocatalytic reaction between iodate and arsenous acid in a Hele-Shaw cell. In the low frequency range covered by the experiments, the front behavior is controlled by the flow across the gap and is reproduced with two-dimensional numerical simulations. It is shown that the front velocity oscillates at the frequency of the flow, whereas the front width oscillates at twice that frequency. Moreover, the Taylor regime in the presence of a Poiseuille flow is fully investigated: The description obtained in the case of a stationary flow provides an analytical prediction for the sinusoidal flow. The range of parameters, for which the prediction applies, is delineated and discussed.

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“…These fronts are analogous to flames in combustion [4] and autocatalytic reactions are a kind of "cold combustion model" especially in the thin flame limit. In contrast to flame propagation in combustion [4], where it has been analyzed thoroughly theoretically and experimentally, the effect of fluid flow (laminar or turbulent) on reaction fronts has not been explored in detail until recently [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. In the presence of an hydrodynamic flow, it has already been observed and understood that such fronts while propagating at a new constant velocity, adapt their shape in order to achieve a balance between reaction diffusion and flow advection.…”

Section: Introductionmentioning

confidence: 99%

Frozen fronts selection in flow against self-sustained chemical waves

Chevalier

¹

,

Salin

²

,

Talon

³

2017

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Autocatalytic reaction fronts between two reacting species in the absence of fluid flow, propagate as solitary waves. The coupling between autocatalytic reaction front and forced hydrodynamic flow may lead to stationary front whose velocity and shape depend on the underlying flow field. We focus on the issue of the chemo-hydrodynamic coupling between forced advection opposed to self-sustained chemical waves which can lead to static stationary fronts, i.e Frozen Fronts, F F . Towards that purpose, we perform experiments, analytical computations and numerical simulations with the autocatalytic Iodate Arsenious Acid reaction (IAA) over a wide range of flow velocities around a solid disk. For the same set of control parameters, we observe two types of frozen fronts: an upstream F F which avoid the solid disk and a downstream F F with two symmetric branches emerging from the solid disk surface. We delineate the range over which we do observe these Frozen Fronts. We also address the relevance of the so-called eikonal, thin front limit to describe the observed fronts and select the frozen front shapes.

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Propagation velocities of chemical reaction fronts advected by Poiseuille flow

Cited by 10 publications

References 33 publications

CHEMO-hydrodynamic coupling between forced advection in porous media and self-sustained chemical waves

CHEMO-hydrodynamic coupling between forced advection in porous media and self-sustained chemical waves

Taylor’s regime of an autocatalytic reaction front in a pulsative periodic flow

Frozen fronts selection in flow against self-sustained chemical waves

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