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Ebullition en écoulement à flux thermique élevé dans des microcanaux multiples en silicone. II. Caractéristiques du transfert de chaleur du frigorigène R245fa.

High heat flux flow boiling in silicon multi-microchannels. II. Heat transfer characteristics of refrigerant R245fa.

Auteurs : AGOSTINI B., THOME J. R., FABBRI M., et al.

Type d'article : Article

Résumé

This second part focuses on flow boiling heat transfer of refrigerant R245fa in a silicon multi-microchannel heat sink and their comparison with the results presented in part I for refrigerant R236fa. This heat sink was the same as utilized in part I. The test conditions covered base heat fluxes from 3.6 to 190 W/cm2, mass velocities from 281 to 1501 kg/m2 s and the exit vapour qualities from 0 to 78%. The effect of saturation pressure on heat transfer was tested from 141 to 273 kPa for R245fa and the effect of sub-cooling from 0 to 19 K. The R245fa database includes 693 local heat transfer coefficient measurements, for which four different heat transfer trends were identified, although in most cases the heat transfer coefficient increased with heat flux, was almost independent of vapour quality and increased with mass velocity. The entire database, including both R245fa and R236fa measurements, was compared with four prediction methods for flow boiling heat transfer in microchannels. The three-zone model of Thome et al. was found to give the best predictions, capturing 90% of the data within plus or minus 30% in the slug and annular flow regimes. [Reprinted with permission from Elsevier. Copyright, 2008]. See also this Bulletin, references 2009-0059 and 0060.

Détails

  • Titre original : High heat flux flow boiling in silicon multi-microchannels. II. Heat transfer characteristics of refrigerant R245fa.
  • Identifiant de la fiche : 2009-0061
  • Langues : Anglais
  • Source : International Journal of Heat and Mass Transfer - vol. 51 - n. 21-22
  • Date d'édition : 10/2008

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