Dynamics of premixed hydrogen/air flames in microchannels

Pizza, Gianmarco; Frouzakis, Christos E.; Mantzaras, John; Tomboulides, Ananias; Boulouchos, Konstantinos

doi:10.1016/j.combustflame.2007.07.013

Cited by 193 publications

(165 citation statements)

References 28 publications

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“…Notice that the flame behavior described here using the thermo-diffusive approximation reproduces qualitatively well the results reported by Pizza et al in [13] in their full-chemistry, direct numerical simulation of lean / ¼ 0:5 hydrogen premixed flames propagating in a microchannel.…”

Section: Very Diffusive Fuels Le F ¼ 0:3supporting

confidence: 87%

“…These works showed that stoichiometric or near-stoichiometric mixtures give stable flames in the high and low incoming velocity regions and unstable flames in the middle velocity region, with flame extinctions and re-ignitions that are repeated periodically in time. A similar instability has been observed by Richecoeour and Kyritsis [11] and Evans and Kyritsis [12] for rich flames propagating in curved ducts and by Pizza et al [13] and Kurdyumov et al [14] for lean flames propagating in a bidimensional micro-channel.…”

Section: Introductionsupporting

confidence: 79%

“…According to Pizza et al [13] and Kurdyumov et al [14], the flamebecomes more unstable in a wider range of mass flow rates as the height of the channel is increased in lean / ¼ 0:5 and very lean flames / ! 0, respectively.…”

Section: The Size Matters: the Effect Of The Damkhôler Number Dmentioning

confidence: 97%

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Effect of the equivalence ratio, Damköhler number, Lewis number and heat release on the stability of laminar premixed flames in microchannels

Sánchez–Sanz

Fernández-Galisteo

Kurdyumov

2014

Combustion and Flame

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This is a postprint version of the following published document:Sánchez-Sanz, M. ; Fernández-Galisteo, D. ; Kurdyumov, V. N. Effect of the equivalence ratio, Damköhler number, Lewis number and heat release on the stability of laminar premixed flames in microchannels. Combustion and Flame, 2014, 161 (5) The effect of the equivalence ratio on the stability and dynamics of a premixed flame in a planar microchannel with a step-wise wall temperature profile is numerically investigated using the thermo-diffusive approximation. To characterize the stability behavior of the flame, we construct the stability maps delineating the regions with different flame dynamics in the inlet mass flow rate m vs. the equivalence ratio / parametric space. The flame stability is analyzed for fuels with different diffusivity by changing the Lewis numbers in the range 0:3 6 Le F 6 1:4. On the other hand, the Lewis number of the oxidizer is kept constant and equal to unity Le O ¼ 1. Our results show that, for very diffusive fuels, the stability of the flame varies significantly with the equivalence ratio, transitioning from stable flames for lean mixtures to highly unstable flames when / > 1. As the fuel Lewis number approaches unity, the stability behavior of the flame for lean and rich mixtures becomes more similar to give, in the equidiffusional case Le F ¼ 1, a symmetric stability map around the stoichiometric mixture / ¼ 1. In all cases considered, the most stable flames are always found around the stoichiometric mixtures / ¼ 1, when the flame instabilities are completely suppressed for very diffusive fuels Le F < 1, or are reduced to a narrow range of inflow velocities for fuel Lewis numbers equal or greater than unity.The ratio between the size of the channel and the flame thickness d turns out to be of great importance in the stability behavior of the flame. Keeping the rest of parameters constant, an increase in d for lean flames makes the flame considerably more unstable, confirming the findings of previous works. Nevertheless, as the stoichiometric ratio approaches / ¼ 1, that trend is reversed to give flames that become more stable as the size of the channel is increased.

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Section: Very Diffusive Fuels Le F ¼ 0:3supporting

confidence: 87%

Section: Introductionsupporting

confidence: 79%

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Effect of the equivalence ratio, Damköhler number, Lewis number and heat release on the stability of laminar premixed flames in microchannels

Sánchez–Sanz

Fernández-Galisteo

Kurdyumov

2014

Combustion and Flame

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show abstract

“…On the other hand, flame dynamics, such as FREI, have been numerically confirmed by Jackson et al [28] in the 1D straight microchannel and by Pizza et al [29] in 2D planar microchannel. However, none of the flame patterns observed in our 2D radial microchannel has been captured by numerical simulations to date.…”

Section: Introductionmentioning

confidence: 85%

Experimental and numerical investigations of flame pattern formations in a radial microchannel

Fan

Minaev

Sereshchenko

et al. 2009

Proceedings of the Combustion Institute

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“…Although numerous studies have investigated the flame patterns generated in micro-combustors [3][4][5][6], specific knowledge of the dynamics of the flame propagation within the channels is still lacking. This lack of information on the flame dynamics has hindered the successful development of combustion-based MEMS.…”

Section: Introductionmentioning

confidence: 99%