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Mesure des coefficients de transfert de chaleur lors de l'ébullition de frigorigènes dans un faisceau de tubes ailetés simulant un faisceau entier.

Measurement of spray boiling refrigerant coefficients in an integral-fin tube bundle segment simulating a full bundle.

Auteurs : TATARA R. A., PAYVAR P.

Type d'article : Article, Article de la RIF

Résumé

Outside (refrigerant) boiling coefficients for a combination of spray and drip boiling for a low pressure refrigerant have been obtained from overall heat transfer coefficients in a 1024 fins per meter tube bundle segment. The tubes were heated by water on the inside; liquid refrigerant was sprayed and/or dripped on the outside. Also, refrigerant vapour was supplied at the bottom of the bundle segment. This configuration simulates an actual flooded evaporator under spray boiling conditions. The dripping corresponds to liquid film falling from upper rows while the inlet vapour is equivalent to the vaporized refrigerant rising from lower tubes; the refrigerant vapour can influence heat transfer performance by the combined effects of gas convection and liquid shear on the tubes. For a nominal heat flux of 23,975 W/m2, a bundle average outside heat transfer coefficient of 8522 W/m2.°C, based on nominal tube outer diameter, was found at an average bundle vapour mass flux equal to 12.4 kg/s.m2. The distributor plate below the bundle enhanced the heat transfer, especially at lower vapour mass fluxes, by providing a level of liquid hold-up just below the bottom tube row.

Documents disponibles

Format PDF

Pages : 744-754

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 : Measurement of spray boiling refrigerant coefficients in an integral-fin tube bundle segment simulating a full bundle.
  • Identifiant de la fiche : 2002-1265
  • Langues : Anglais
  • Source : International Journal of Refrigeration - Revue Internationale du Froid - vol. 24 - n. 8
  • Date d'édition : 12/2001

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