Numerical simulation of aluminum dust counterflow flames
Notice bibliographique
Résumé
<sec>Aluminum is widely used as an additive in solid rocket propellants and pyrotechnics due to its outstanding characteristics such as high energy density and combustion temperature, environmentally benign products, and good stability. Recently, aluminum powders are found to present great potential serving as alternative fuel in a low-carbon economy. In this paper, a detailed model including the effects of interphase heat transfer, phase change, heterogeneous surface reactions, homogeneous combustion and radiation is employed to investigate aluminum dust counterflow flames.</sec><sec>The numerical model is first validated by simulating the aluminum dust counterflow flames of McGill University. The results indicate that the particle velocity profile is in very good agreement with the experimental measurements. A detailed analysis of estimating the gas phase velocity based on the particle velocity is performed by using Stoke time <i>τ</i><sub>s</sub>. The results show that a correct value of <i>τ</i><sub>s</sub> is the key to this method, and using a single value of <i>τ</i><sub>s</sub> can bring a notable bias to the results, which may also affect the evaluation of flame speed from the counterflow flame. It is suggested that model validation should be carried out by directly comparing the particle velocity profiles from the simulations with those from the experiments. The flame structure of the aluminum dust counterflow flame is discussed, and the interphase heat transfer model is found to have a great influence on the flame for particle sizes smaller than 10 μm. Therefore, when simulating the aluminum dust flames with small particle sizes, the interphase heat transfer model should be selected carefully so that it can cover the transition heat transfer regime. The effect of particle diameter is examined. With the increase of the particle size, the flame speed continues to decrease, and most particles with a diameter of 15 μm cannot be fully burnt in the present configuration. The strain rate is found to be an important factor affecting the dust flame. As the strain rate increases, the residence time of the particles in the flame zone decreases, which ultimately leads the particles to be combusted incompletely. Moreover, the reaction zone of the counterflow flame, marked as AlO, is observed to be shrunk from a large double-peak structure into a small single-peak one along the burner centerline when strain increases. The reference flame speed increases with strain rate, and an unstretched reference flame speed of roughly 29 cm/s can be obtained by linear extrapolation of the predicted results. The effect of radiation is investigated by comparing two cases with and without radiative heat transfer. The results show that the heat loss caused by radiation can lead the temperature to decrease greatly in the gas phase, but the heating effect on the particles by radiation is relativelysmall.</sec>
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 | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
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; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».