Comparison between experimental measurements and numerical calculations of the structure of counterflow, diluted, methane-air, premixed flames

Smooke, Mitchell D.; Crump, J. E.; Seshadri, K.; Giovangigli, Vincent

doi:10.1016/s0082-0784(06)80292-4

Cited by 52 publications

(44 citation statements)

References 12 publications

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“…[20]. The complete formulation of the mathematical model for solving the finite burner separation problem with plug flow boundary conditions [21,22] starts with the elliptic form, in cylindrical coordinates, of the two-dimensional equations describing the conservation of total mass, individual chemical species mass, momentum, and energy for the reactive flow occurring between the fuel and the AP solid. By seeking a similarity solution of the governing equations, we can reduce the problem to the solution of a nonlinear, two-point boundary value problem in the axial direction along the stagnation point streamline.…”

Section: Computational Approachmentioning

confidence: 99%

Computational and experimental study of ammonium perchlorate/ethylene counterflow diffusion flames

Smooke

Yetter

Parr

et al. 2000

Proceedings of the Combustion Institute

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Section: Computational Approachmentioning

confidence: 99%

Computational and experimental study of ammonium perchlorate/ethylene counterflow diffusion flames

Smooke

Yetter

Parr

et al. 2000

Proceedings of the Combustion Institute

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“…It is well known, that flame stretch -defined as the fractional rate of change of the flame surface area [6] -can decrease heat release rates and even lead to flame extinction of laminar flames [7,8]. Under non-adiabatic conditions, flames are more sensitive to effects of strain [9,10]. Indeed, due to the high flame temperatures, cooling of the combustor walls is required to ensure the mechanical integrity of the system.…”

Section: Introductionmentioning

confidence: 99%

“…Arrows indicate velocities of planar stagnation flow. At low to moderate strain rates, the reaction zone of the flame (indicated by the right line) is to the right of the stagnation point of the flow products [7][8][9][10][40][41][42][43][44]. In both cases, the strain rate is uniform over the flame surface with no curvature effects.…”

Section: Introductionmentioning

confidence: 99%

Combined Influence of Strain and Heat Loss on Turbulent Premixed Flame Stabilization

Tay-Wo-Chong

Zellhuber

Komarek

et al. 2015

Flow Turbulence Combust

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The present paper argues that the prediction of turbulent premixed flames under non-adiabatic conditions can be improved by considering the combined effects of strain and heat loss on reaction rates. The effect of strain in the presence of heat loss on the consumption speed of laminar premixed flames was quantified by calculations of asymmetric counterflow configurations ("fresh-to-burnt") with detailed chemistry. Heat losses were introduced by setting the temperature of the incoming stream of products on the "burnt" side to values below those corresponding to adiabatic conditions. The consumption speed decreased in a roughly exponential manner with increasing strain rate, and this tendency became more pronounced in the presence of heat losses. An empirical relation in terms of Markstein number, Karlovitz Number and a non-dimensional heat loss parameter was proposed for the combined influence of strain and heat losses on the consumption speed. Combining this empirical relation with a presumed probability density function for strain in turbulent flows, an attenuation factor that accounts for the effect of strain and heat loss on the reaction rate in turbulent flows was deduced and implemented into a turbulent combustion model. URANS simulations of a premixed swirl burner were carried out and validated against flow field and OH chemiluminescence measurements. Introducing the effects of Wolfgang Polifke Flow Turbulence Combust strain and heat loss into the combustion model, the flame topology observed experimentally was correctly reproduced, with good agreement between experiment and simulation for flow field and flame length.

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“…The numerical simulation of the counterflow diffusion flame was obtained solving the mass, momentum, energy, and species conservation equations along the stagnation streamline using a model described in Ref. [14], where the pertinent conservation equations and the employed boundary and initial conditions are described in detail. An existing numerical code [14], developed to simulate steady counterflow diffusion flames, was modified by introducing a backward Euler approximation for the evaluation of the time derivatives in the conservation equations.…”

Section: Numerical Approachmentioning

confidence: 99%

“…[14], where the pertinent conservation equations and the employed boundary and initial conditions are described in detail. An existing numerical code [14], developed to simulate steady counterflow diffusion flames, was modified by introducing a backward Euler approximation for the evaluation of the time derivatives in the conservation equations. The numerical model used detailed chemical kinetics (GRI version 2.11 [15], 48 species and 275 reactions), and transport properties.…”

Section: Numerical Approachmentioning

confidence: 99%

Nitric oxide formation during flame/vortex interaction

Santoro

Kyritsis

Smooke

et al. 2002

Proceedings of the Combustion Institute

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The formation of nitric oxide was investigated in methane diffusion flames under the perturbation of laminar vortices. Laser-induced fluorescence and Raman spectroscopy were used to measure nitric oxide, major species, and temperature, and to obtain the time evolution of the scalar dissipation rate at the stoichiometric surface during the flame/vortex interaction. Vortices with two characteristic times were thrust into the flame and their effects were compared with steady flames at the same scalar dissipation rate. The experimental measurements showed that the vortex did not affect significantly the peak temperature, CO, and CO 2 mass fraction during the interaction. NO, instead, was strongly affected. The peak mass fraction of NO in flames under vortex perturbation differed by almost a factor of 2 from steady flames with similar scalar dissipation rates. One-dimensional numerical simulations, used under the well-justified assumption that the vortices induced negligible curvature, yielded results in good agreement with the experimental measurements. The numerical computations were also used to investigate the effect of the characteristic time of the vortex on the different NO formation paths, that is, thermal, and prompt. The peak mass fraction of thermal NO was shown to be strongly dependent on the timescale of the unsteady perturbation, while prompt NO was almost independent. The emission index, that is, the production of NO normalized by the consumption of the fuel, behaved quasi-steadily for the two formation paths. The results were rationalized by considering the flame structure and the activation energy of the different formation paths.

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Comparison between experimental measurements and numerical calculations of the structure of counterflow, diluted, methane-air, premixed flames

Cited by 52 publications

References 12 publications

Computational and experimental study of ammonium perchlorate/ethylene counterflow diffusion flames

Computational and experimental study of ammonium perchlorate/ethylene counterflow diffusion flames

Combined Influence of Strain and Heat Loss on Turbulent Premixed Flame Stabilization

Nitric oxide formation during flame/vortex interaction

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