Research on the Condensation Process of Gaseous Water and Water/Ethanol Mixture in the Laval Nozzle
Notice bibliographique
Résumé
Abstract Condensation phenomenon has been studied actively for decades because of its extensive and significant applications in various fields of technology and engineering. The condensation phenomenon of condensable component in supersonic flows is still not understood very well as a result of the complex nucleation and droplet growth process, especially the condensation characteristic of gas mixture. In this paper, the Laval nozzle was designed based on the bi-cubic curve, state equation of real gas, arc plus straight line and viscous correction of boundary layer. The physical and mathematical models were developed to predict the condensation process in the supersonic air flows based on the nucleation and droplet growth theories, surface tension model and gas-liquid governing equations. The condensation processes of gaseous water/air binary (single condensable) gas and water/ethanol/air ternary (double condensable) gas mixture in the designed nozzle were simulated, and the reliability of the established models was verified by the experimental data. By comparing the condensation process of water/air binary gas with water/ethanol ternary gas, the influence of the second condensable component on the condensation process was analyzed. The results show that in the condensation process of gaseous water, as the pressure and temperature of water vapor decrease in the nozzle, spontaneous condensation occurs further downstream the nozzle throat. The nucleation rate grows rapidly from 0 to peak in a very short distance. With the consumption of water vapor, due to the decrease of the degree of supercooling, the nucleation environment is destroyed, and the nucleation rate quickly decreases to 0. The nucleation process is rapid in time and space, while the droplet growth process could maintain longer. The droplet number and mass fraction increase continuously till the nozzle outlet. There is a weak condensation in the nozzle due to the release of latent heat, but it is not obvious because the air acts as a heat container and absorbs the latent heat released by condensation. In the water/ethanol/air ternary system, the ethanol nucleates prior to water vapor. With the increase of supercooling, water vapor also begins to nucleate. In essence, there are two kinds of condensation nuclei (water nuclei and ethanol nuclei), and both the water and ethanol vapor can aggregate on these two kinds of condensation nuclei. Compared with the condensation process of water, the Wilson point of condensation is closer to the throat and the outlet mass fraction of liquid phase is greater in the condensation process of water/ethanol mixture, which shows that the water and ethanol can affect and promote each other. The maximum nucleation rate, droplet growth rate, droplet radius and outlet mass fraction of liquid phase of water/air binary and water/ethanol/air ternary mixture are about 9.46 × 1026 m−3s−1 and 2.57 × 1027 m−3s−1, 1.65 × 10−5 m/s and 1.02 × 10−5m/s, 1.32 × 10−7m and 1.63 × 10−7m, 0.19% and 1.34%, respectively.
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 | 0,002 | 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 ».