Quenching and pollutant emissions in side-wall and head-on NH <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si69.svg" display="inline" id="d1e710"> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:msub> </mml:math> /H <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si71.svg" display="inline" id="d1e718"> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:math> /N <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si71.svg" display="inline" id="d1e726"> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:math> premixed laminar flames
Notice bibliographique
Résumé
We present quenching distance, wall heat loss, and pollutant emission results from a series of simulations of NH 3 /H 2 /N 2 premixed laminar flames in side-wall and head-on quenching configurations. Conditions cover lean to rich mixtures (equivalence ratio from 0.3 to 1.2) at both atmospheric and moderate (10 atm) pressures. For each set of conditions, two-dimensional “V”-flame simulations with side-wall quenching (SWQ) and with symmetric boundary conditions are compared to isolate wall heat loss from curvature effects. Simulations of one-dimensional head-on quenched (HOQ) flames covering the same range of conditions are also included for further comparison. First, a non-monotonic relationship between quenching Peclet number and equivalence ratio is found at 10 atm for both SWQ and HOQ, attributed to a significant change in flame structure at lean conditions, with the Jiang chemical kinetics mechanism. Second, wall heat loss normalized by laminar flame power is lower for HOQ flames, compared to SWQ, at lean conditions and higher at rich conditions, which is attributed to the effect of flame curvature on heat release rate in SWQ flames. Yet, normalized wall heat loss shows a similar correlation with quenching Peclet number for both pressures and quenching configurations. Third, similar to previously reported experimental results, we find that ammonia slip increases due to wall heat loss and curvature effects, while hydrogen slip departs negligibly from that of unstretched laminar flames. The contrast with ammonia slip is striking at low equivalence ratio and is attributed to the strongly diverging flux of hydrogen near the quenching point, promoting its consumption. Fourth, both wall heat loss and negative flame curvature at the wall significantly reduce NO emissions as the rates of NO forming reaction pathways are diminished. In the SWQ cases, NO consuming pathways are comparatively less inhibited, being in part fed by NO diffusing towards the wall from non-quenched regions. Finally, both negative curvature at the wall and wall heat loss increase N 2 O emissions. A non-monotonic relationship between N 2 O emissions and equivalence ratio is observed at elevated pressure, as the rate of the N 2 O consuming reaction increases for equivalence ratios below 0.6. Novelty and significance statement We present the first flame-resolved simulations at elevated pressure of side-wall quenching (SWQ) and head-on quenching (HOQ) in NH 3 /H 2 flames. The range of equivalence ratios covered also extends to leaner conditions than previously investigated in both HOQ and SWQ NH 3 /H 2 flames (relevant to staged gas turbine combustors). The one-to-one comparison between 1D HOQ, 2D adiabatic, and 2D SWQ NH 3 /H 2 flames is also novel, and reveals key insights on the effect of preferential diffusion on flame quenching and emissions. The results provide foundational insights that can be used to better understand and model flame-wall interaction in practical NH 3 /H 2 combustion devices.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,006 | 0,007 |
| Méta-épidémiologie (sens strict) | 0,005 | 0,008 |
| Méta-épidémiologie (sens large) | 0,002 | 0,005 |
| Bibliométrie | 0,003 | 0,005 |
| Études des sciences et des technologies | 0,005 | 0,006 |
| Communication savante | 0,004 | 0,006 |
| Science ouverte | 0,007 | 0,008 |
| Intégrité de la recherche | 0,009 | 0,009 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,063 | 0,003 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; les deux têtes enseignantes s’accordent sur ce qui est montré ici.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».