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The contact angle of nanofluids as thermophysical property

Hernaiz, M. ; Alonso, V. ; Estellé, P. ; Wu, Z. LU ; Sundén, B. LU ; Doretti, L. ; Mancin, S. ; Çobanoğlu, N. ; Karadeniz, Z. H. and Garmendia, N. , et al. (2019) In Journal of Colloid and Interface Science 547. p.393-406
Abstract

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... (More)

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.

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Contribution to journal
publication status
published
subject
keywords
Contact angle, Experimental strategy, Influence of temperature, Influence of volume, Nanofluids, Round robin test
in
Journal of Colloid and Interface Science
volume
547
pages
14 pages
publisher
Elsevier
external identifiers
  • pmid:30974254
  • scopus:85063930459
ISSN
0021-9797
DOI
10.1016/j.jcis.2019.04.007
language
English
LU publication?
yes
id
c4016d79-5ee1-4c44-a120-0c05a8aa3276
date added to LUP
2019-04-24 12:59:16
date last changed
2020-03-24 06:46:56
@article{c4016d79-5ee1-4c44-a120-0c05a8aa3276,
  abstract     = {<p>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.</p>},
  author       = {Hernaiz, M. and Alonso, V. and Estellé, P. and Wu, Z. and Sundén, B. and Doretti, L. and Mancin, S. and Çobanoğlu, N. and Karadeniz, Z. H. and Garmendia, N. and Lasheras-Zubiate, M. and Hernández López, L. and Mondragón, R. and Martínez-Cuenca, R. and Barison, S. and Kujawska, A. and Turgut, A. and Amigo, A. and Huminic, G. and Huminic, A. and Kalus, M. R. and Schroth, K. G. and Buschmann, M. H.},
  issn         = {0021-9797},
  language     = {eng},
  pages        = {393--406},
  publisher    = {Elsevier},
  series       = {Journal of Colloid and Interface Science},
  title        = {The contact angle of nanofluids as thermophysical property},
  url          = {http://dx.doi.org/10.1016/j.jcis.2019.04.007},
  doi          = {10.1016/j.jcis.2019.04.007},
  volume       = {547},
  year         = {2019},
}