Dropwise condensation heat transfer process optimisation on superhydrophobic surfaces using a multi-disciplinary approach

Z. Khatir, K. J. Kubiak, P. K. Jimack, T. G. Mathia

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Dropwise condensation has superior heat transfer efficiency than filmwise condensation; however condensate evacuation from the surface still remains a significant technological challenge. The process of droplets jumping, against adhesive forces, from a solid surface upon coalescence has been studied using both experimental and Computational Fluid Dynamics (CFD) analysis. Both Lattice Boltzmann (LBM) and Volume of Fluid (VOF) methods have been used to evaluate different kinematic conditions of coalescence inducing a jump velocity. In this paper, an optimisation framework for superhydrophobic surface designs is presented which uses experimentally verified high fidelity CFD analyses to identify optimal combinations of design features which maximise desirable characteristics such as the vertical velocity of the merged jumping droplet from the surface and energy efficiency. A Radial Basis Function (RBF)-based surrogate modelling approach using Design of Experiment (DOE) technique was used to establish near-optimal initial process parameters around which to focus the study. This multidisciplinary approach allows us to evaluate the jumping phenomenon for superhydrophobic surfaces for which several input parameters may be varied, so as to improve the heat transfer exchange rate on the surface during condensation. Reliable conditions were found to occur for droplets within initial radius range of r = 20-40 μm and static contact angle θs ∼ 160°. Moreover, the jumping phenomenon was observed for droplets with initial radius of up to 500 μm. Lastly, our study also reveals that a critical contact angle for droplets to jump upon coalescence is θc ∼ 140°.

LanguageEnglish
Pages1337-1344
Number of pages8
JournalApplied Thermal Engineering
Volume106
Early online date21 Jun 2016
DOIs
Publication statusPublished - 5 Aug 2016

Fingerprint

Condensation
Heat transfer
Coalescence
Contact angle
Computational fluid dynamics
Design of experiments
Dynamic analysis
Energy efficiency
Adhesives
Kinematics
Fluids

Cite this

Khatir, Z. ; Kubiak, K. J. ; Jimack, P. K. ; Mathia, T. G. / Dropwise condensation heat transfer process optimisation on superhydrophobic surfaces using a multi-disciplinary approach. In: Applied Thermal Engineering. 2016 ; Vol. 106. pp. 1337-1344.
@article{2496042f38ec48fd9f3853b0d824a14e,
title = "Dropwise condensation heat transfer process optimisation on superhydrophobic surfaces using a multi-disciplinary approach",
abstract = "Dropwise condensation has superior heat transfer efficiency than filmwise condensation; however condensate evacuation from the surface still remains a significant technological challenge. The process of droplets jumping, against adhesive forces, from a solid surface upon coalescence has been studied using both experimental and Computational Fluid Dynamics (CFD) analysis. Both Lattice Boltzmann (LBM) and Volume of Fluid (VOF) methods have been used to evaluate different kinematic conditions of coalescence inducing a jump velocity. In this paper, an optimisation framework for superhydrophobic surface designs is presented which uses experimentally verified high fidelity CFD analyses to identify optimal combinations of design features which maximise desirable characteristics such as the vertical velocity of the merged jumping droplet from the surface and energy efficiency. A Radial Basis Function (RBF)-based surrogate modelling approach using Design of Experiment (DOE) technique was used to establish near-optimal initial process parameters around which to focus the study. This multidisciplinary approach allows us to evaluate the jumping phenomenon for superhydrophobic surfaces for which several input parameters may be varied, so as to improve the heat transfer exchange rate on the surface during condensation. Reliable conditions were found to occur for droplets within initial radius range of r = 20-40 μm and static contact angle θs ∼ 160°. Moreover, the jumping phenomenon was observed for droplets with initial radius of up to 500 μm. Lastly, our study also reveals that a critical contact angle for droplets to jump upon coalescence is θc ∼ 140°.",
keywords = "Condensation heat transfer, Jumping droplets velocity, Multi-disciplinary optimisation, Super-hydrophobic surface",
author = "Z. Khatir and Kubiak, {K. J.} and Jimack, {P. K.} and Mathia, {T. G.}",
year = "2016",
month = "8",
day = "5",
doi = "10.1016/j.applthermaleng.2016.06.128",
language = "English",
volume = "106",
pages = "1337--1344",
journal = "Applied Thermal Engineering",
issn = "1359-4311",
publisher = "Elsevier",

}

Dropwise condensation heat transfer process optimisation on superhydrophobic surfaces using a multi-disciplinary approach. / Khatir, Z.; Kubiak, K. J.; Jimack, P. K.; Mathia, T. G.

In: Applied Thermal Engineering, Vol. 106, 05.08.2016, p. 1337-1344.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Dropwise condensation heat transfer process optimisation on superhydrophobic surfaces using a multi-disciplinary approach

AU - Khatir, Z.

AU - Kubiak, K. J.

AU - Jimack, P. K.

AU - Mathia, T. G.

PY - 2016/8/5

Y1 - 2016/8/5

N2 - Dropwise condensation has superior heat transfer efficiency than filmwise condensation; however condensate evacuation from the surface still remains a significant technological challenge. The process of droplets jumping, against adhesive forces, from a solid surface upon coalescence has been studied using both experimental and Computational Fluid Dynamics (CFD) analysis. Both Lattice Boltzmann (LBM) and Volume of Fluid (VOF) methods have been used to evaluate different kinematic conditions of coalescence inducing a jump velocity. In this paper, an optimisation framework for superhydrophobic surface designs is presented which uses experimentally verified high fidelity CFD analyses to identify optimal combinations of design features which maximise desirable characteristics such as the vertical velocity of the merged jumping droplet from the surface and energy efficiency. A Radial Basis Function (RBF)-based surrogate modelling approach using Design of Experiment (DOE) technique was used to establish near-optimal initial process parameters around which to focus the study. This multidisciplinary approach allows us to evaluate the jumping phenomenon for superhydrophobic surfaces for which several input parameters may be varied, so as to improve the heat transfer exchange rate on the surface during condensation. Reliable conditions were found to occur for droplets within initial radius range of r = 20-40 μm and static contact angle θs ∼ 160°. Moreover, the jumping phenomenon was observed for droplets with initial radius of up to 500 μm. Lastly, our study also reveals that a critical contact angle for droplets to jump upon coalescence is θc ∼ 140°.

AB - Dropwise condensation has superior heat transfer efficiency than filmwise condensation; however condensate evacuation from the surface still remains a significant technological challenge. The process of droplets jumping, against adhesive forces, from a solid surface upon coalescence has been studied using both experimental and Computational Fluid Dynamics (CFD) analysis. Both Lattice Boltzmann (LBM) and Volume of Fluid (VOF) methods have been used to evaluate different kinematic conditions of coalescence inducing a jump velocity. In this paper, an optimisation framework for superhydrophobic surface designs is presented which uses experimentally verified high fidelity CFD analyses to identify optimal combinations of design features which maximise desirable characteristics such as the vertical velocity of the merged jumping droplet from the surface and energy efficiency. A Radial Basis Function (RBF)-based surrogate modelling approach using Design of Experiment (DOE) technique was used to establish near-optimal initial process parameters around which to focus the study. This multidisciplinary approach allows us to evaluate the jumping phenomenon for superhydrophobic surfaces for which several input parameters may be varied, so as to improve the heat transfer exchange rate on the surface during condensation. Reliable conditions were found to occur for droplets within initial radius range of r = 20-40 μm and static contact angle θs ∼ 160°. Moreover, the jumping phenomenon was observed for droplets with initial radius of up to 500 μm. Lastly, our study also reveals that a critical contact angle for droplets to jump upon coalescence is θc ∼ 140°.

KW - Condensation heat transfer

KW - Jumping droplets velocity

KW - Multi-disciplinary optimisation

KW - Super-hydrophobic surface

UR - http://www.scopus.com/inward/record.url?scp=84976637482&partnerID=8YFLogxK

U2 - 10.1016/j.applthermaleng.2016.06.128

DO - 10.1016/j.applthermaleng.2016.06.128

M3 - Article

VL - 106

SP - 1337

EP - 1344

JO - Applied Thermal Engineering

T2 - Applied Thermal Engineering

JF - Applied Thermal Engineering

SN - 1359-4311

ER -