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Condensation et transfert de chaleur et chute de pression de NH3 à l'intérieur d'un tube lisse.

NH3 in-tube condensation heat transfer and pressure drop in a smooth tube.

Auteurs : PARK C. Y., HRNJAK P.

Type d'article : Article, Article de la RIF

Résumé

This paper presents an overview of the issues and new results for in-tube condensation of ammonia in horizontal round tubes. A new empirical correlation is presented based on measured NH3 in-tube condensation heat transfer and pressure drop by Komandiwirya et al. An experimental investigation of pressure drop and heat transfer in an in-tube condensation system of ammonia with and without miscible oil in smooth and enhanced tubes. ACRC CR-54, University of Illinois at Urbana-Champaign] in an 8.1 mm aluminium tube at a saturation temperature of 35°C, and for a mass flux range of 20-270 kg m2/s. Most correlations overpredict these measured NH3 heat transfer coefficients, up to 300%. The reasons are attributed to difference in thermophysical properties of ammonia compared to other refrigerants used in generation and validation of the correlations. Based on the conventional correlations, thermophysical properties of ammonia, and measured heat transfer coefficients, a new correlation was developed which can predict most of the measured values within plus or minus 20%. Measured NH3 pressure drop is shown and discussed. Two separated flow models are shown to predict the pressure drop relatively well at pressure drop higher than 1 kPa/m, while a homogeneous model yields acceptable values at pressure drop less than 1 kPa/m. The pressure drop mechanism and prediction accuracy are explained though the use of flow patterns.

Documents disponibles

Format PDF

Pages : 643-651

Disponible

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    20 €

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    Gratuit

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Détails

  • Titre original : NH3 in-tube condensation heat transfer and pressure drop in a smooth tube.
  • Identifiant de la fiche : 2008-1526
  • Langues : Anglais
  • Source : International Journal of Refrigeration - Revue Internationale du Froid - vol. 31 - n. 4
  • Date d'édition : 06/2008

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