CFD Simulations in Ansys CFX of Plate Heat Exchanger Channels using Fanning Friction Factor and Nusselt Number
Notice bibliographique
Résumé
In this master thesis computational fluid dynamic simulations of two plate heat exchanger channels have been performed in Ansys CFX. The full geometry of the channels has not been included, the channels were modeled with a flat geometry instead of a corrugated pattern. To account for the effect of the corrugation on the pressure drop, one-time pressure losses and momentum sources were added in the model. The momentum sources were related to the Fanning friction factor, which in turn was related to the Reynolds number by experimental correlations provided by Alfa Laval. The heat transfer was modeled with a thermal contact resistance between the hot and the cold channels. The contact resistance included the heat transfer coefficient for the hot and the cold fluid, calculated from Nusselt numbers. The Nusselt numbers were obtained from experimental correlations provided by Alfa Laval, based on values for the Reynolds number and the Prandtl number. Three different channel designs with different geometries were simulated, and the results were compared to Alfa Laval’s design program for plate heat exchangers. Each channel design was simulated with correlations for both high theta pattern and low theta pattern for the corrugations. The resulting pressure drop for the high theta pattern was generally accurate with a maximum difference of -13% to +6% compared to the reference. For the low theta pattern the pressure drop difference varied between -20% to +13% for two of the channel designs, while the last design was more than 50% off. The reason for why the low theta pattern is harder to simulate is believed to be some problem with the momentums sources in the distribution areas of the channels. In a high theta channel, a small share of the pressure drop occurs in the distribution area resulting in a small pressure drop deviation. In a low theta channel, a major part of the pressure occurs in the distribution area, leading to larger deviations. The heat transfer was considered accurate for all channels and patterns, with a maximum deviation of 2% of the outlet temperatures. The model can be used in early design stages of new channel geometries to give an indication of the expected performance. The model can also be used to replace detailed simulations in specific parts of the channels, while the other parts are simulated with the corrugation geometry. The model is not suitable for simulating new corrugation patterns since it is based on correlations from existing patterns. (Less)
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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 ».