The contact angle of nanofluids as thermophysical property
Scholar | Other documents of the author: Hernaiz, M.; Alonso, V.; estellé, patrice; Wu, Z.; Sundén, B.; Doretti, L.; mancin, simone; Çobanoğlu, N.; Karadeniz, Z. H.; Garmendia, N.; Lasheras-Zubiate, L.; Hernández López, Leonor; Mondragón Cazorla, Rosa; Martínez Cuenca, Raúl; Barison, Simona; Kujawska, A.; Turgut, A.; Amigo, A.; HUMINIC, Gabriela; Huminic, Angel; Kalus, M.-R.; Schroth, K.-G.; Buschmann, M.H.
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TitleThe contact angle of nanofluids as thermophysical property
Droplet volume and temperature affect contact angle significantly. Phase change heat transfer processes of nanofluids – suspensions containing nanometre-sized particles – can only be modelled properly by understanding ... [+]
Droplet volume and temperature affect contact angle significantly. Phase change heat transfer processes of nanofluids – suspensions containing nanometre-sized particles – can only be modelled properly by understanding these effects. The approach proposed here considers the limiting contact angle of a droplet asymptotically approaching zero-volume as a thermophysical property to characterise nanofluids positioned on a certain substrate under a certain atmosphere. Graphene oxide, alumina, and gold nanoparticles are suspended in deionised water. Within the framework of a round robin test carried out by nine independent European institutes the contact angle of these suspensions on a stainless steel solid substrate is measured with high accuracy. No dependence of nanofluids contact angle of sessile droplets on the measurement device is found. However, the measurements reveal clear differences of the contact angle of nanofluids compared to the pure base fluid. Physically founded correlations of the contact angle in dependency of droplet temperature and volume are obtained from the data. Extrapolating these functions to zero droplet volume delivers the searched limiting contact angle depending only on the temperature. It is for the first time, that this specific parameter, is understood as a characteristic material property of nanofluid droplets placed on a certain substrate under a certain atmosphere. Together with the surface tension it provides the foundation of proper modelling phase change heat transfer processes of nanofluids. [-]
Investigation projectCOST (European Cooperation in Science and Technology) (COST Action CA15119 NANOUPTAKE) ; Bundesministerium für Wirtschaft und Energie (Germany) (grant 49VF 170005) ; Spanish Ministry of Economy and Competitiveness and the UE FEDER programme (grants ENE2014-55489-C2-1-R and ENE2017-86425-C2-2-R).
Bibliographic citationHERNAIZ, M., et al. The contact angle of nanofluids as thermophysical property. Journal of colloid and interface science, 2019, 547: 393-406.
© 2019 Published by Elsevier Inc.
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