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Nanoparticules pour l'amélioration du transfert de chaleur d'évaporation.

Nanoparticles to enhance evaporative heat transfer.

Auteurs : PARK Y., SOMMERS A., LIU L., et al.

Résumé

The purpose of this study was to determine the effect of very dilute concentrations of nanoparticles on the evaporative heat transfer of R-134a. Various nanoparticle/halocarbon combinations were prepared to check for dispersion compatibility including Al(2)O(3)/R-134a, Cu/R-134a, carbon nanotubes/R-134a, and SiO2/R-134a. The dispersion compatibility of other refrigerants such as R-22 and R-404A were also explored. In most cases, the dispersed particles agglomerated in the liquid and exhibited very rapid settling. However, in a few specific cases, the particles settled more slowly such that under normal flow conditions where mixing is present, the system may be able to maintain a good dispersion of nanoparticles. One such identified combination was SiO2/R-134a. For this combination, experiments were conducted with and without nanoparticle seeding in a conventional two-phase single-pass loop at a single volume fraction of 0.50%. The average aggregate length of these treated fumed silica particles was 200-300 nm while individual particles were tens of nanometers in size. The results show that the boiling heat transfer coefficient was reduced approximately 30% due to the nanoparticles in the refrigerant.

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Format PDF

Pages : ICR07-B1-709

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    20 €

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Détails

  • Titre original : Nanoparticles to enhance evaporative heat transfer.
  • Identifiant de la fiche : 2007-2491
  • Langues : Anglais
  • Source : ICR 2007. Refrigeration Creates the Future. Proceedings of the 22nd IIR International Congress of Refrigeration.
  • Date d'édition : 21/08/2007

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