scholarly journals An efficient flamelet progress-variable method for modeling non-premixed flames in weak electric fields

2017 ◽  
Vol 157 ◽  
pp. 14-27 ◽  
Author(s):  
M. Di Renzo ◽  
P. De Palma ◽  
M.D. de Tullio ◽  
G. Pascazio
Keyword(s):  
Electric Fields ◽  
Premixed Flames ◽  
Variable Method ◽  
Progress Variable

scholarly journals Assessment of Extrapolation Relations of Displacement Speed for Detailed Chemistry Direct Numerical Simulation Database of Statistically Planar Turbulent Premixed Flames

2021 ◽  
Author(s):  
Nilanjan Chakraborty ◽  
Alexander Herbert ◽  
Umair Ahmed ◽  
Hong G. Im ◽  
Markus Klein
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Premixed Flames ◽  
Turbulent Premixed Flames ◽  
Reaction Progress ◽  
Progress Variable ◽  
Stretch Rate ◽  
Non Linear ◽  
Displacement Speed ◽  
Curvature Dependence

AbstractA three-dimensional Direct Numerical Simulation (DNS) database of statistically planar $$H_{2} -$$ H 2 - air turbulent premixed flames with an equivalence ratio of 0.7 spanning a large range of Karlovitz number has been utilised to assess the performances of the extrapolation relations, which approximate the stretch rate and curvature dependences of density-weighted displacement speed $$S_{d}^{*}$$ S d ∗ . It has been found that the correlation between $$S_{d}^{*}$$ S d ∗ and curvature remains negative and a significantly non-linear interrelation between $$S_{d}^{*}$$ S d ∗ and stretch rate has been observed for all cases considered here. Thus, an extrapolation relation, which assumes a linear stretch rate dependence of density-weighted displacement speed has been found to be inadequate. However, an alternative extrapolation relation, which assumes a linear curvature dependence of $$S_{d}^{*}$$ S d ∗ but allows for a non-linear stretch rate dependence of $$S_{d}^{*}$$ S d ∗ , has been found to be more successful in capturing local behaviour of the density-weighted displacement speed. The extrapolation relations, which express $$S_{d}^{*}$$ S d ∗ as non-linear functions of either curvature or stretch rate, have been found to capture qualitatively the non-linear curvature and stretch rate dependences of $$S_{d}^{*}$$ S d ∗ more satisfactorily than the linear extrapolation relations. However, the improvement comes at the cost of additional tuning parameter. The Markstein lengths LM for all the extrapolation relations show dependence on the choice of reaction progress variable definition and for some extrapolation relations LM also varies with the value of reaction progress variable. The predictions of an extrapolation relation which involve solving a non-linear equation in terms of stretch rate have been found to be sensitive to the initial guess value, whereas a high order polynomial-based extrapolation relation may lead to overshoots and undershoots. Thus, a recently proposed extrapolation relation based on the analysis of simple chemistry DNS data, which explicitly accounts for the non-linear curvature dependence of the combined reaction and normal diffusion components of $$S_{d}^{*}$$ S d ∗ , has been shown to exhibit promising predictions of $$S_{d}^{*}$$ S d ∗ for all cases considered here.

scholarly journals A priori investigation of subgrid correlation of mixture fraction and progress variable in partially premixed flames

2018 ◽  
Vol 22 (5) ◽  
pp. 862-882 ◽  
Author(s):  
Zhi X. Chen ◽  
N. Anh Khoa Doan ◽  
Shaohong Ruan ◽  
Ivan Langella ◽  
N. Swaminathan
Keyword(s):  
Mixture Fraction ◽  
A Priori ◽  
Premixed Flames ◽  
Progress Variable ◽  
Partially Premixed Flames ◽  
Partially Premixed

A Non-Adiabatic Flamelet Progress–Variable Approach for LES of Turbulent Premixed Flames

2011 ◽  
Vol 86 (3-4) ◽  
pp. 667-688 ◽  
Author(s):  
Donato Cecere ◽  
Eugenio Giacomazzi ◽  
Franca R. Picchia ◽  
Nunzio Arcidiacono ◽  
Filippo Donato ◽  
...  
Keyword(s):  
Premixed Flames ◽  
Turbulent Premixed Flames ◽  
Progress Variable ◽  
Variable Approach ◽  
Turbulent Premixed
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