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Une étude expérimentale de la performance du transfert de chaleur lors de l’ébullition en écoulement du R245fa dans des tubes horizontaux et verticaux.

An experimental investigation of R245fa flow boiling heat transfer performance in horizontal and vertical tubes.

Auteurs : CAO S., WANG G., WU X., YANG W., HU C.

Type d'article : Article de la RIF

Résumé

An experimental investigation of R245fa flow boiling in the horizontal flow (θfd = 0°), vertical upward flow (θfd = 90°), and vertical downward flow (θfd = –90°) was carried out using a bare stainless-steel tube (BT) with an inner diameter of 10.02 mm and an effective heating length of 820 mm. The experimental condition was performed under a saturation pressure of 0.6 MPa, a heat flux varying from 4.99–74.60 kW/m2, a mass flux range of 197.94–696.63 kg/(m2·s), and a vapour quality range from 0.01 to 0.9. Five flow patterns, stratified flow, intermittent flow, churn flow, annular flow, and drying flow, could be observed in the experiment. When the heat flux was relatively low (q ≤ 15 kW/m2)), the variation of the heat transfer coefficient with flow direction was relatively gradual. However, when q ≥ 30 kW/m2, a distinct 'U'-shaped trend in the heat transfer coefficient is observed with the flow direction transitioning from vertical downward to horizontal and then to vertical upward. Due to the effect of buoyancy force, the heat transfer performance was relatively better at θfd = –90° The friction pressure drop in the horizontal flow was the smallest, and the maximum value always occurred at θfd = 90° Meanwhile, the experimental data for heat transfer coefficient and pressure drop was compared to the well-known correlations from the literature. The predictive correlation by Fang et al. for the heat transfer coefficient was in good agreement with the experimental data. Regarding frictional pressure drop, the Filho, Muller-Steinhagen and Heck and Zakaria correlations were recommended for pressure drop in horizontal flow, upward flow, and downward flow, respectively.
 

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Format PDF

Pages : 229-245

Disponible

  • Prix public

    20 €

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    Gratuit

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Détails

  • Titre original : An experimental investigation of R245fa flow boiling heat transfer performance in horizontal and vertical tubes.
  • Identifiant de la fiche : 30032260
  • Langues : Anglais
  • Sujet : Technologie
  • Source : International Journal of Refrigeration - Revue Internationale du Froid - vol. 160
  • Date d'édition : 04/2024
  • DOI : http://dx.doi.org/10.1016/j.ijrefrig.2024.02.008

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