Strained flamelets for turbulent premixed flames, I: Formulation and planar flame results
- Department of Engineering, Cambridge University, Cambridge CB2 1PZ (United Kingdom)
A strained flamelet model is proposed for turbulent premixed flames using scalar dissipation rate as a parameter. The scalar dissipation rate of reaction progress variable is a suitable quantity to describe the flamelet structure since it is governed by convection-diffusion-reaction balance and it is defined at every location in the flamelets, which are represented by laminar flames in reactant-to-product opposed flow configuration. The mean reaction rate is obtained by using the flamelets reaction rate and the joint pdf of the progress variable and its dissipation rate. The marginal pdf of the progress variable is presumed to be {beta}-pdf and the pdf of the conditional dissipation rate is taken to be log-normal. The conditional mean dissipation rate is obtained from modelled mean dissipation rate. This reaction rate closure is assessed using RANS calculations of statistically planar flames in the corrugated flamelets and thin reaction zones regimes. The flame speeds calculated using this closure are close to the experimental data of Abdel-Gayed et al. (1987) for flames in both the regimes. Comparisons with other reaction rate closures showed the benefits of the strained flamelets approach. (author)
- OSTI ID:
- 21305713
- Journal Information:
- Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 5 Vol. 157; ISSN CBFMAO; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COMBUSTION KINETICS
COMPARATIVE EVALUATIONS
CONVECTION
DIFFUSION
FLAME PROPAGATION
Flamelet modelling
LAMINAR FLAMES
MATHEMATICAL MODELS
PROBABILITY DENSITY FUNCTIONS
SCALARS
SIMULATION
Scalar dissipation rate
Strained flamelets
TURBULENCE
Turbulent premixed flames
VELOCITY
ZONES