Comparaison et généralisation de la distribution du R410A et du R134a dans un échangeur de chaleur à microcanaux avec un collecteur vertical.

Comparison and generalization of R410A and R134a distribution in the microchannel heat exchanger with the vertical header.

Numéro : pap. 2122

Auteurs : ZOU Y., HRNJAK P.

Résumé

This paper explores the effects of fluid properties on two-phase flow in the vertical header and refrigerant distribution into horizontal branch tubes. R410A and R134a are used as the working fluid. Refrigerant enters into the header by five microchannel tubes in the bottom pass and exits through the five microchannel tubes in the top pass representing the flow in the outdoor microchannel heat exchanger of reversible systems under heat pump mode. The difference of fluid properties causes the flow pattern and refrigerant distribution results of R410A and R134a different between each other. Non-dimensional analysis shows that the inertia of R410A is higher than that of R134a. At low qualities, when the flow regime is churn, the higher inertia enables top tubes to receive more liquid so that the distribution of R410A is a little better than that of R134a. At high qualities, when it is likely semiannular, the higher inertia causes more bottom tubes are bypassed by the liquid film of semi-annular flow. It results in worse R410A distribution than R134a, though more liquid reaches the top tubes for R410A. The coefficient of variation of refrigerant distribution is applied in this study to generalize the results of both R410A and R134a at various header geometries and inlet flow conditions. A distribution function is derived for predicting R410A and R134a distribution in future.

Documents disponibles

Format PDF

Pages : 10 p.

Disponible

  • Prix public

    20 €

  • Prix membre*

    15 €

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

Détails

  • Titre original : Comparison and generalization of R410A and R134a distribution in the microchannel heat exchanger with the vertical header.
  • Identifiant de la fiche : 30013021
  • Langues : Anglais
  • Source : 2014 Purdue Conferences. 15th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Date d'édition : 14/07/2014

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