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Etude expérimentale du développement et du détachement des bulles dans les écoulements ascendant et descendant de l'ébullition.

An experimental investigation of bubble growth and detachment in vertical upflow and downflow boiling.

Auteurs : THORNCROFT G. E., KLAUSNER J. F., MEI R.

Type d'article : Article

Résumé

High-speed digital images of flow boiling phenomena were obtained, which were used to measure bubble growth, departure diameters, and lift-off diameters. The observed vapour bubble dynamics between upflow and downflow are significantly different. In the upflow configuration, bubbles departing the nucleation site slide along the heater wall, and typically do not lift off. In the downflow configuration, bubbles either lift off directly from the nucleation site or slide and then lift off, depending on flow and thermal conditions. The process of vapour bubble sliding appears to be responsible for enhanced energy transfer from the heating surface, as evidenced by larger heat transfer coefficients for upflow than for downflow under otherwise identical operating conditions.

Détails

  • Titre original : An experimental investigation of bubble growth and detachment in vertical upflow and downflow boiling.
  • Identifiant de la fiche : 1999-3435
  • Langues : Anglais
  • Source : International Journal of Heat and Mass Transfer - vol. 41 - n. 23
  • Date d'édition : 12/1998

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