Partager

Document IIF

Etude expérimentale de chute de pression diphasique dans des coudes de retour horizontaux avec de l'ammoniac.

Experimental study of two-phase pressure-drop in horizontal return bends with ammonia.

Auteurs : MUZAFFAR A., ABBAS A., CREMASCHI L., AYUB Z.

Type d'article : Article de la RIF

Résumé

In evaporators and condensers of refrigeration and air conditioning systems, various straight tubes are joined via U-bends. These U-bends result in higher pressure drops due to flow disturbances and centrifugal effects. Accurate prediction of pressure drops in these bends is essential for reliable design and operation. This study investigates the two-phase flow pressure-drop in horizontal U-bends with ammonia under wide range of experimental conditions. Three pipes with nominal outer diameter between 22.2, 15.9, and 9.5 mm were used, each with three bend radii (R/do ratio) between 1.2 and 2.5 in horizontal configuration. Tests were conducted at saturation temperature of +10 and -15 °C, with mass flux varying between 10 and 50 kg m−2 s−1, and vapor quality between 0.1 and 0.9. The pressure-drop increased with mass flux and vapor quality while decreased with saturation temperature, pipe diameter and R/do ratio of the bend.
Large tubes exhibited a greater increase in pressure drop with rising mass flux and decreasing bend ratio compared to small tubes, which showed higher absolute values and more consistent performance across the vapor quality range at both saturation temperatures. The tube diameter had a less significant effect at high saturation temperature and high mass flux, while the bend curvature ratio predominantly influenced the pressure drop performance for large diameter tubes. One correlation from the literature predicted the data well only if the vapor quality was below 0.5. For wider range of quality, the existing models in the literature were not well-suited for predicting pressure drops in ammonia U-bends.

Documents disponibles

Format PDF

Pages : 593-606

Disponible

  • Prix public

    20 €

  • Prix membre*

    Gratuit

* meilleur tarif applicable selon le type d'adhésion (voir le détail des avantages des adhésions individuelles et collectives)

Détails

  • Titre original : Experimental study of two-phase pressure-drop in horizontal return bends with ammonia.
  • Identifiant de la fiche : 30032883
  • Langues : Anglais
  • Source : International Journal of Refrigeration - Revue Internationale du Froid - vol. 168
  • Date d'édition : 12/2024
  • DOI : http://dx.doi.org/10.1016/j.ijrefrig.2024.09.021

Liens


Voir d'autres articles du même numéro (63)
Voir la source

Indexation