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Investigation of pool boiling critical heat flux enhancement on a modified surface through the dynamic wetting of water droplets / Ho Seon Ahn in Journal of heat transfer, Vol. 134 N° 7 (Juillet 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol. 134 N° 7 (Juillet 2012) . - 13 p. Titre : Investigation of pool boiling critical heat flux enhancement on a modified surface through the dynamic wetting of water droplets Type de document : texte imprimé Auteurs : Ho Seon Ahn, Auteur ; Joonwon Kim, Auteur ; Moo Hwan Kim, Auteur Année de publication : 2012 Article en page(s) : 13 p. Note générale : heat transfer Langues : Anglais (eng) Mots-clés : pool  boiling;  critical  heat  flux;  dynamic  wetting;  microstructure;  nanostructure Index. décimale : 536 Chaleur. Thermodynamique Résumé : Dynamic wetting behaviors of water droplet on the modified surface were investigated experimentally. Dynamic contact angles were measured as a characterization method to explain the extraordinary pool boiling critical heat flux (CHF) enhancement on the zirconium surface by anodic oxidation modification. The sample surface is rectangular zirconium alloy plates (20 × 25 × 0.7 mm), and 12 µl of deionized water droplets were fallen from 40 mm of height over the surface. Dynamic wetting movement of water on the surface showed different characteristics depending on static contact angle (49.3 deg–0 deg) and surface temperature (120 °C–280 °C). Compared with bare surface, wettable and spreading surface had no-receding contact angle jump and seemed stable evaporating meniscus of liquid droplet in dynamic wetting condition on hot surface. This phenomenon could be explained by the interaction between the evaporation recoil and the surface tension forces. The surface tension force increased by micro/nanostructure of the modified zirconium surface suppresses the vapor recoil force by evaporation which makes the water layer unstable on the heated surface. Thus, such increased surface force could sustain the water layer stable in pool boiling CHF condition so that the extraordinary CHF enhancement could be possible. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000007 [...] [article] Investigation of pool boiling critical heat flux enhancement on a modified surface through the dynamic wetting of water droplets [texte imprimé] / Ho Seon Ahn, Auteur ; Joonwon Kim, Auteur ; Moo Hwan Kim, Auteur . - 2012 . - 13 p. heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol. 134 N° 7 (Juillet 2012) . - 13 p. Mots-clés : pool  boiling;  critical  heat  flux;  dynamic  wetting;  microstructure;  nanostructure Index. décimale : 536 Chaleur. Thermodynamique Résumé : Dynamic wetting behaviors of water droplet on the modified surface were investigated experimentally. Dynamic contact angles were measured as a characterization method to explain the extraordinary pool boiling critical heat flux (CHF) enhancement on the zirconium surface by anodic oxidation modification. The sample surface is rectangular zirconium alloy plates (20 × 25 × 0.7 mm), and 12 µl of deionized water droplets were fallen from 40 mm of height over the surface. Dynamic wetting movement of water on the surface showed different characteristics depending on static contact angle (49.3 deg–0 deg) and surface temperature (120 °C–280 °C). Compared with bare surface, wettable and spreading surface had no-receding contact angle jump and seemed stable evaporating meniscus of liquid droplet in dynamic wetting condition on hot surface. This phenomenon could be explained by the interaction between the evaporation recoil and the surface tension forces. The surface tension force increased by micro/nanostructure of the modified zirconium surface suppresses the vapor recoil force by evaporation which makes the water layer unstable on the heated surface. Thus, such increased surface force could sustain the water layer stable in pool boiling CHF condition so that the extraordinary CHF enhancement could be possible. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000007 [...]