Effect of Surface Tension and Gas–Liquid Density Ratio on the Wave Height and Interfacial Shear Stress in Annular Flows
Notice bibliographique
Résumé
In the past decades, the liquid film characteristics of annular flow, such as film thickness and wave height, have been studied extensively.However, most experimental data and analyses available in the literature are limited to the air-water annular flows under near-atmospheric condition, thus the variation in surface tension and gas-liquid density are limited and not well-understood [1][2][3][4].In this study, water and ethanol were used as working liquids, whereas nitrogen and HFC134a gas were used as working gases.The surface tension ranges from 30.7 to 67.4 mN/m and density ratio ranges from 27 to 434.The conductance probe method was used to measure the time-varying liquid film thickness [5].Two sets of sensors with an accuracy of 5% were installed in the test section for the film thickness measurement.The base, average, and maximum film thickness, together with wave height, were obtained after post-processing.Meanwhile, a differential pressure transducer was installed to measure the differential pressure at 0.5-0.105m downstream the inlet of the test section.The experimental results show that the base film thickness collapses onto a single curve under the same liquid flow rate when plotted against either gas Weber number or interfacial shear stress acting on the base film, even though the surface tension and density ratio vary in current experiments.It may be concluded that the effect of the surface tension on the base film thickness is relatively small.However, both the maximum film thickness and the height of disturbance wave collapse onto a single curve under the same liquid flow rate when plotted against the gas Weber number rather than the interfacial shear stress.The reason behind this may be that the surface tension tends to retain the shape of the wave crest against the interfacial shear stress.Therefore, the shape of the disturbance wave is decided by the balance between the surface tension and the interfacial shear stress which are reflected in the gas Weber number.Additionally, a direct relationship between the height of disturbance wave and interfacial shear stress was identified, providing a potential method to estimate shear stress from wave characteristics.These findings enhance the understanding of annular flow dynamics and contribute to improving the two-phase flow modelling.Moreover, this work may also contribute to advance the understanding of two-phase flows and support to a wide range of applications, including nuclear power, aerospace, chemical industries, and the development of next-generation cooling systems.
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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 ».