Partager

Document IIF

Transfert de chaleur à l'intérieur des tubes et caractéristiques de chute de pression du NH3 pur et du CO2 dans les systèmes frigorifiques.

In-tube heat transfer and pressure drop characteristics of pure NH3 and CO2 in refrigeration systems.

Auteurs : HRNJAK P. S., PARK C. Y.

Résumé

This paper analyzes the differences and similarities between heat transfer in ammonia and carbon dioxide from the perspective of NH3 two-stage, CO2/NH3 cascade, NH3 direct expansion, and CO2 direct expansion systems heat exchanger designer. The focus is on differences in thermophysical properties and thus different performances. Besides a literature review of available correlations, some new experimental data are presented. Because of large deviation of calculated values with exiting correlations from measured results, two new correlations to predict flow condensation heat transfer coefficients are developed based on experimental results for NH3 at 35°C and CO2 at -15°C. With comparison of measured and predicted values, it is shown that some correlations, previously published in open literature, can be used to calculate flow boiling heat transfer coefficients for NH3 at -20°C, CO2 at -30°C and heat transfer coefficient for CO2 gas cooling process. It is shown that some correlations proposed by previous studies can predict the pressure drop with NH3 and CO2 two-phase flow, and with CO2 gas cooling process, relatively well. The NH3 and CO2 flow evaporation heat transfer and pressure drop characteristics at -40°C are compared with predicted values.

Documents disponibles

Format PDF

Pages : 2007-2

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 : In-tube heat transfer and pressure drop characteristics of pure NH3 and CO2 in refrigeration systems.
  • Identifiant de la fiche : 2007-1993
  • Langues : Anglais
  • Source : Ammonia Refrigeration Technology for Today and Tomorrow.
  • Date d'édition : 19/04/2007

Liens


Voir d'autres communications du même compte rendu (31)
Voir le compte rendu de la conférence

Indexation