Impact of chemistry models on flame–vortex interaction

Lapointe, Simon; Bobbitt, Brock; Blanquart, Guillaume

doi:10.1016/j.proci.2014.06.091

Cited by 9 publications

(5 citation statements)

References 21 publications

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“…The chemical source terms are determined through a single irreversible, one-step reaction. The same equation is solved as in the work of Lapointe et al, 59 but with a different fuel. The rate constant, A, and activation temperature, T a , are chosen so that the 1D unstretched laminar flame speed and thickness closely match that of the finite-rate mechanism (A = 6.0 × 10 9 m 3 /kg s and T a = 15 000 K).…”

Section: B Effect Of Chemical Modelsmentioning

confidence: 99%

Vorticity transformation in high Karlovitz number premixed flames

2016

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To better understand the two-way coupling between turbulence and chemistry, the changes in turbulence characteristics through a premixed flame are investigated. Specifically, this study focuses on vorticity, ω, which is characteristic of the smallest length and time scales of turbulence, analyzing its behavior within and across high Karlovitz number (Ka) premixed flames. This is accomplished through a series of direct numerical simulations (DNS) of premixed n-heptane/air flames, modeled with a 35-species finite-rate chemical mechanism, whose conditions span a wide range of unburnt Karlovitz numbers and flame density ratios. The behavior of the terms in the enstrophy, ω2 = ω ⋅ ω, transport equation is analyzed, and a scaling is proposed for each term. The resulting normalized enstrophy transport equation involves only a small set of parameters. Specifically, the theoretical analysis and DNS results support that, at high Karlovitz number, enstrophy transport obtains a balance of the viscous dissipation and production/vortex stretching terms. It is shown that, as a result, vorticity scales in the same manner as in homogeneous, isotropic turbulence within and across the flame, namely, scaling with the inverse of the Kolmogorov time scale, τη. As τη is a function only of the viscosity and dissipation rate, this work supports the validity of Kolmogorov’s first similarity hypothesis in premixed turbulent flames for sufficiently high Ka numbers. Results are unaffected by the transport model, chemical model, turbulent Reynolds number, and finally the physical configuration.

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Section: B Effect Of Chemical Modelsmentioning

confidence: 99%

Vorticity transformation in high Karlovitz number premixed flames

2016

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“…Reactions shown in Eqs. (21)(22)(23)(24)(25) are used to model the air mixture that includes five species: N 2 , O 2 , NO, O, and N. The vector of mass fractions of the mixture, Y, is defined to be…”

Section: Overview Of Air Test Casesmentioning

confidence: 99%

“…The fastest reaction mode represents a linear combination of some or all of the original five reactions [Eqs. (21)(22)(23)(24)(25)]. As this mode equilibrates quicker than the other two modes in the system, this "pseudo" reaction should not affect the value of the chosen constraint.…”

Section: Table 4 Global Constraint Examplesmentioning

confidence: 99%

“…The previous five reactions used for the air system [Eqs. (21)(22)(23)(24)(25)] are still used, and in addition the following reactions are included:…”

Section: Extension To the Martian Atmospherementioning

confidence: 99%

“…The RCCE method has been applied successfully to laminar and turbulent flames under low Mach conditions in the past [13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Unfortunately, there is little available data detailing the performance of the RCCE method for compressible flows [31,32], and none of it pertains to hypervelocity conditions.…”

Section: Introductionmentioning

confidence: 99%

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