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Etude expérimentale et analytique de l'effet de l'angle de contact sur le transfert de chaleur lors de la convection dans les microcanaux.

Experimental and analytical study of the effect of contact angle on liquid convective heat transfer in microchannels.

Auteurs : ROSENGARTEN G., COOPER-WHITE J., METCALFE G.

Type d'article : Article

Résumé

In this paper, the authors examine the effect of contact angle (or surface wettability) on the convective heat transfer coefficient in microchannels. Slip flow, where the fluid velocity at the wall is non-zero, is most likely to occur in microchannels due to its dependence on shear rate or wall shear stress. They show analytically that for a constant pressure drop, the presence of slip increases the Nusselt number. In a microchannel heat exchanger they modified the surface wettability from a contact angle of 20°-120° using thin film coating technology. Apparent slip flow is implied from pressure and flow rate measurements with a departure from classical laminar friction coefficients above a critical shear rate of approximately 10,000/s. The magnitude of this departure is dependant on the contact angle with higher contact angles surfaces exhibiting larger pressure drop decreases. Similarly, the non-dimensional heat flux is found to decrease relative to laminar non-slip theory, and this decrease is also a function of the contact angle. Depending on the contact angle and the wall shear rate, variations in the heat transfer rate exceeding 10% can be expected. Thus the contact angle is an important consideration in the design of micro, and even more so, nano heat exchangers. [Reprinted with permission from Elsevier. Copyright, 2006].

Détails

  • Titre original : Experimental and analytical study of the effect of contact angle on liquid convective heat transfer in microchannels.
  • Identifiant de la fiche : 2007-1016
  • Langues : Anglais
  • Source : International Journal of Heat and Mass Transfer - vol. 49 - n. 21-22
  • Date d'édition : 10/2006

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