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Transfert de chaleur et chute de pression lors de la condensation du frigorigène R404A à des pressions proches de la zone critique.

Heat transfer and pressure drop for condensation of refrigerant R404A at near-critical pressures.

Auteurs : JIANG Y., GARIMELLA S.

Résumé

The paper presents the results of an experimental study on heat transfer and pressure drop during condensation of refrigerant R404A inside a horizontal 9.4 mm ID tube. The experiments were conducted at nominal pressures of 80 and 90% of the critical pressure of R404A. A novel technique that addresses the conflicting requirements imposed by the need for accurate measurement of low heat transfer rates for the small quality increments, and delineation of the tube-side heat transfer coefficient from the overall resistance, was developed. Local heat transfer coefficients and pressure drops were measured in small quality increments over the entire vapour-liquid region, spanning several different two-phase flow regimes. These data were compared with existing correlations for condensation heat transfer to assess the validity of these models for this high-pressure refrigerant blend when operating near the critical pressure. The high reduced pressures in the study result in deviations from the predictions of the commonly used condensation heat transfer correlations, although the model by Cavallini et al. showed reasonable agreement with the heat transfer data from the study.

Détails

  • Titre original : Heat transfer and pressure drop for condensation of refrigerant R404A at near-critical pressures.
  • Identifiant de la fiche : 2005-1161
  • Langues : Anglais
  • Source : ASHRAE Transactions. 2003 Winter Meeting, Chicago, Illinois. Volume 109, part 1 + CD-ROM.
  • Date d'édition : 2003

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