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Caractéristiques et stabilité d'un film d'eau en surfusion entraîné par le vent sur une surface glacée. I. Transfert de chaleur laminaire.

Character and stability of a wind-driven supercooled water film on an icing surface. I. Laminar heat transfer.

Auteurs : KAREV A. R., FARZANEH M., LOZOWSKI E. P.

Type d'article : Article

Résumé

The kinetics of freezing of a supercooled water film flowing on an icing surface are considered here for the case of laminar heat transfer through the water film. The linear growth rate of crystallization (LRC) in a supercooled, laminar water film, flowing over an accreting ice surface, was found to be characterized by unique behaviour at different length scales. The icing surface is envisaged as a semi-infinite horizontal flat plate with vertically impinging supercooled water droplets. The water film begins to develop at the edge of the plate and thickens while it collects impinging water as the horizontal wind stress drives it downstream. At very short distances from the Couette flow origin, where convection prevails over conduction through the water film, the LRC reacts in a stable fashion to instantaneous changes in the external thermodynamic parameters. The LRC accelerates or decelerates, responding to variations in the water film thickness. At intermediate distances from the flow origin, the LRC is independent of sudden perturbations in the water film thickness, and is determined only by the mean external parameters that characterize the heat transfer and flow dynamics at the water film surface. At a still greater distance from the flow origin, the LRC is unstable in a shear-driven, supercooled water film, flowing over an accreting ice surface. The instability gives rise to either complete disappearance of the water film or a total change of the momentum and heat transfer regime (see also this Bulletin, reference 2004 - 2651).

Détails

  • Titre original : Character and stability of a wind-driven supercooled water film on an icing surface. I. Laminar heat transfer.
  • Identifiant de la fiche : 2004-2650
  • Langues : Anglais
  • Source : International Journal of thermal Sciences - vol. 42 - n. 5
  • Date d'édition : 05/2003

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