Validation of State-of-the-Art LES Modelling for Soot Prediction in Rich Premixed Turbulent Flames: a Focus on Oxidation Processes
Résumé
The availability of large eddy simulations (LES) models for the prediction of soot production in complex configurations is essential to the design of the new generation of combustion systems. This requires a good understanding of the processes leading to soot production and the development and validation of the corresponding models. This motivates the present calculations carried out for a laboratory scale burner (EM2Soot) designed at the EM2C laboratory to study soot production in turbulent swirled flames operating under fully-premixed rich conditions. The laser induced incandescence (LII) imaging data for the soot volume fraction (SVF) are used to test the validity of state-of-the-art numerical LES models for soot prediction. The retained models aim at achieving a good level of accuracy for a reasonable computational cost. The gaseous species kinetics is described with an analytically-reduced chemistry approach while the soot solid phase is computed using a three-equation model. This numerical strategy qualitatively reproduces the SVF in laminar premixed flames. In the considered turbulent burner, the numerical strategy captures the SVF spatial distribution but the predicted yield is notably overestimated with respect to the LII results. An extensive analysis of the flame structure as well as of the soot source terms indicates that this is due to an underestimation of soot oxidation reactions. A parametric study on rich laminar and turbulent flames is then carried out to examine the effect of soot oxidation model on the SVF prediction. This indicates that it is worth testing soot models in turbulent flame conditions to examine their capacities and reveal their shortcomings. It is also concluded that the EMSoot configuration offers an interesting situation for developing and validating soot oxidation models.
Domaines
Milieux fluides et réactifsOrigine | Fichiers produits par l'(les) auteur(s) |
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