Thermal resistance of heated superhydrophobic channels with thermocapillary stress
Author(s)
Tomlinson, SD
Mayer, MD
Kirk, TL
Hodes, M
Papageorgiou, DT
Type
Journal Article
Abstract
A pressure-driven channel flow between a longitudinally ridged superhydrophobic surface (SHS) and solid wall is studied, where a constant heat flux enters the channel from either the SHS or solid wall. First, a model is developed which neglects thermocapillary stresses (TCS) in the transverse direction. The caloric, convective, and total thermal resistance are evaluated, and their dependence on the shape of the liquid–gas interface (meniscus), gas ridge width, texture period, channel height, streamwise TCS, Péclet number, and channel length is established. The caloric resistance is minimized with menisci that protrude into the gas cavity, large slip fractions, small channel heights, and small streamwise TCSs. When heating from the SHS, the convective resistance increases, and therefore, a design compromise exists between caloric and convective resistances. However, when heating from the solid wall, the convective resistance remains the same and SHSs that minimize caloric resistance are optimal. We investigate both water and Galinstan for microchannel applications and find that both configurations can have a lower total thermal resistance than a smooth-walled channel. Heating from the solid wall is shown to always have the lowest total thermal resistance. Numerical simulations are used to analyze the effect of transverse TCSs. Our model captures much of the physics in heated superhydrophobic channels but is computationally inexpensive when compared to the numerical simulations.
Date Issued
2024-02-01
Date Acceptance
2023-11-01
Citation
ASME Journal of Heat and Mass Transfer, 2024, 146 (2)
ISSN
0017-9310
Publisher
ASME
Journal / Book Title
ASME Journal of Heat and Mass Transfer
Volume
146
Issue
2
Copyright Statement
Copyright © 2024 by ASME. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Identifier
https://asmedigitalcollection.asme.org/heattransfer/article/146/2/021601/1169664/Thermal-Resistance-of-Heated-Superhydrophobic
Publication Status
Published
Article Number
021601
Date Publish Online
2023-11-09