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2019-09-08 - Colloque/Présentation - communication orale - Anglais - page(s)

De Coninck Joël , "Surface wettability to improve heat transfer" in ECIS 2019, Leuven, Belgique, 2019

  • Codes CREF : Physique (DI1200), Physique des surfaces (DI1265)
  • Unités de recherche UMONS : Laboratoire de Physique des Surfaces et Interfaces (S877)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux), Institut de Recherche sur les Systèmes Complexes (Complexys)
  • Centres UMONS : Ingénierie des matériaux (CRIM)
Texte intégral :

Abstract(s) :

(Anglais) Heat pipe characteristics are linked to the surface properties of the diabatic surfaces, and, in the evaporator, surface properties influence both the onset boiling temperature (TONB) and the critical heat flux (CHF). In this work the effect of surface wettability in pool boiling heat transfer is studied in order to understand if there could be a path to increment heat pipe thermal performance. This work analyses the effects of surface wettability on boiling (tested fluid is pure water) and proposes a new super-hydrophobic polymeric coating which can have a very important effect in improving the heat pipe start-up power load and increasing the thermal performance of heat pipes when the flux is lower than the critical heat flux. The polymeric coating is able to reduce the TONB (-11% from 117°C to about 104°C) compared with the uncoated surfaces, as it inhibits the formation of a vapour film on the solid-liquid interface, avoiding CHT conditions up to maximum wall temperature (125°C). This is realized by the creation of a heterogeneous surface with SHS zones dispersed on top of a hydrophilic surface (stainless steel surface). The proposed coating has an outstanding thermal resistance: No degradation of SH properties of the coating has been observed after more than 500 thermal cycles.