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On the mechanism of dropwise condensation of steam on ion implanted metallic surfaces / Michael H. Rausch in Journal of heat transfer, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 9 (Septembre 2010) . - pp. [094503-1/3] Titre : On the mechanism of dropwise condensation of steam on ion implanted metallic surfaces Type de document : texte imprimé Auteurs : Michael H. Rausch, Auteur ; Alfred Leipertz, Auteur ; Andreas P. Froba, Auteur Article en page(s) : pp. [094503-1/3] Note générale : Physique Langues : Anglais (eng) Mots-clés : Dropwise  condensation  Nucleation  Microscopic  mechanism  Wetting  Ion  implantation Index. décimale : 536 Chaleur. Thermodynamique Résumé : Our recent experimental studies indicate that nanostructured, chemically inhomogeneous surfaces are the origin of dropwise condensation of steam on ion implanted metals. Yet, the underlying microscopic mechanism governing this special condensation form is still not clear. We suggest a condensation model based on droplet nucleation and growth on elevated precipitates, resulting in short-term steam entrapment after droplet coalescence. According to the wetting theory, this transition state yields increased macroscopic contact angles. Condensation phenomena such as enlarging dropwise condensation areas in spite of increasing condensation rate become comprehensible by our model. Furthermore, it points out that for this special surface type, contact angles and surface free energies measured under ambient air conditions are not usable for predicting the condensation form of steam. Although the suggested microscopic model cannot be directly proved by experiment, its validity is supported by its capability of explaining experimental observations colliding with previous theoretical approaches. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] On the mechanism of dropwise condensation of steam on ion implanted metallic surfaces [texte imprimé] / Michael H. Rausch, Auteur ; Alfred Leipertz, Auteur ; Andreas P. Froba, Auteur . - pp. [094503-1/3]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 9 (Septembre 2010) . - pp. [094503-1/3] Mots-clés : Dropwise  condensation  Nucleation  Microscopic  mechanism  Wetting  Ion  implantation Index. décimale : 536 Chaleur. Thermodynamique Résumé : Our recent experimental studies indicate that nanostructured, chemically inhomogeneous surfaces are the origin of dropwise condensation of steam on ion implanted metals. Yet, the underlying microscopic mechanism governing this special condensation form is still not clear. We suggest a condensation model based on droplet nucleation and growth on elevated precipitates, resulting in short-term steam entrapment after droplet coalescence. According to the wetting theory, this transition state yields increased macroscopic contact angles. Condensation phenomena such as enlarging dropwise condensation areas in spite of increasing condensation rate become comprehensible by our model. Furthermore, it points out that for this special surface type, contact angles and surface free energies measured under ambient air conditions are not usable for predicting the condensation form of steam. Although the suggested microscopic model cannot be directly proved by experiment, its validity is supported by its capability of explaining experimental observations colliding with previous theoretical approaches. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]