Lagrangian investigation of local extinction, re-ignition and auto-ignition in turbulent flames

Wang, Haifeng; Pope, Stephen B.

doi:10.1080/13647830802056137

Cited by 43 publications

(36 citation statements)

References 38 publications

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“…In order to deal with realistic conditions while involving a small number of chemical species, we consider a steady lifted H 2 /N 2 turbulent jet flame in a coflow of hot products at atmospheric pressure (the vitiated co-flow burner developed by Dibble and co-workers), first measured at Berkeley university by Cabra et al [16,17] and later at Sydney university at different operating conditions [18,19]. This flame has mainly been modelled in a RANS framework using transported PDF methods with different mixing models [16,[20][21][22][23][24][25][26][27][28]. A first CMC calculation of this flame was reported in [29].…”

Section: Introductionmentioning

confidence: 99%

RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF

Naud

Novella

Pastor

et al. 2015

Combustion and Flame

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Elsevier Naud, B.; Novella Rosa, R.; Pastor Enguídanos, JM.; Winklinger, JF. (2015). RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF. Combustion and Flame. 162 (4) AbstractAn unsteady flamelet / progress variable (UFPV) approach is used to model a lifted H 2 /N 2 flame in a RANS framework together with presumed PDF. We solve the unsteady flamelets both in physical space and in mixture fraction space. We show that in the former case, the scalar dissipation rate profile strongly varies in time (while it is assumed to be fixed in time in the latter). However, this does not result in significant qualitative differences in the corresponding flamelet libraries. The progress variable is carefully defined, including both the main combustion product (H 2 O) and a key radical species in ignition process (HO 2 ). The presumed-PDF model is proposed in terms of the non-normalised progress variable, without assuming its statistical independence with mixture fraction. We introduce a modelled transport equation for the mean progress variable which is consistent with the basic underlying UFPV assumption, derived from the Lagrangian flamelet model. The influence of different model parameters on the results for the mean temperature and mean species mass fractions and their fluctuations is discussed. Good results are obtained for the conditions of the considered lifted flame where detailed experimental data is available. However, at low coflow temperature the modelled flame lift-off height is shorter than expected.

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Section: Introductionmentioning

confidence: 99%

RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF

Naud

Novella

Pastor

et al. 2015

Combustion and Flame

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“…They must be interpreted in a statistical sense. The tracers also do not represent the instantaneous flame structure [36]. Nevertheless, the trajectories in physical space and composition space provide insight in a Lagrangian manner.…”

Section: Particle Tracking Techniquementioning

confidence: 99%

“…A similar technique as in [36] is used to track computational particles. Tracers are randomly selected among the particles introduced into the computational domain at the inlet.…”

Section: Particle Tracking Techniquementioning

confidence: 99%

“…Consequently, if more than one tracer is involved in the clustering, the number of tracers is reduced. In [36] clustering was disabled to avoid this.…”

Section: Particle Tracking Techniquementioning

confidence: 99%

“…In [36] the evolution of the tracers was studied using axial position as surrogate for time. This is not possible for the bluff-body case, as there are several recirculation zones, resulting in a non-monotonous evolution of the axial coordinate with time.…”

Section: Particle Tracking Techniquementioning

confidence: 99%

See 2 more Smart Citations

Transported scalar PDF calculations of a swirling bluff body flame (‘SM1’) with a reaction diffusion manifold

Meester

Naud

Maas

et al. 2012

Combustion and Flame

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The modeling of a reacting swirling flow behind a bluff-body burner (SM1) in the framework of RANS and transported scalar PDF is presented. The EMST mixing model is applied and the composition space is reduced to mixture fraction (Z) and a progress variable (CO 2 mass fraction, Y CO 2 ) by means of a Reaction Diffusion Manifold (REDIM). With an ad hoc adjustment of the turbulent Schmidt number, the mean flow and mixing fields obtained are comparable to LES results from the literature. The REDIM reduction of the composition space to (Z, Y CO 2 ) is discussed and its validity for the present swirling flame is first considered by an a priori comparison with experimental data. The (Z, Y CO 2 )-scatter plots from the transported PDF calculation show the capacity to reproduce the mixing between fresh air and hot products in the recirculation zone above the bluff-body. However, too little scatter is observed. The study of tracer trajectories helps to better understand the capacities and limitations of the modeling approach. Zones where mixing competes with reaction can be identified, and coincide with the highly rotating collar region where local extinction is expected to take place. However, in our modeling, the competition between mixing and reaction is not enough to lead to local extinction. An important modeling deficiency is claimed to be the use of a mean time scale in the EMST mixing model, which limits the possibilities to model high scalar dissipation rate events.

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Probability Density Function Modeling of Turbulent Spray Combustion

Humza

Gutheil

2014

Experiments and Numerical Simulations of Turbulent Combustion of Diluted Sprays

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Lagrangian investigation of local extinction, re-ignition and auto-ignition in turbulent flames

Cited by 43 publications

References 38 publications

RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF

RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF

Transported scalar PDF calculations of a swirling bluff body flame (‘SM1’) with a reaction diffusion manifold

Probability Density Function Modeling of Turbulent Spray Combustion

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