Pattern geometry optimization on superbiphilic aluminum surfaces for enhanced pool boiling heat transfer

Može, Matic (author), Zupančič, Matevž (author), Golobič, Iztok (author)

In this study, the optimal surface pattern of low and high wettability regions for enhanced boiling heat transfer is investigated using aluminum superbiphilic surfaces. Samples are fabricated by combining chemical vapor deposition of a fluorinated silane to turn them superhydrophobic and nanosecond laser texturing to render selected areas superhydrophilic. Triangular lattice pattern of superhydrophobic circular spots is utilized with spot diameters between 0.25 mm and 1.0 mm and pitch values of 0.5-2.5 mm. Pool boiling heat transfer performance of superbiphilic surfaces is evaluated using saturated water at atmospheric pressure. A strong wettability contrast is shown to be important in ensuring high heat transfer performance of wettability-patterned surfaces. Highest heat transfer performance is achieved using 0.5 mm diameter spots with a spot pitch of 1 mm and a corresponding superhydrophobic area fraction of approx. 23%. The optimal pitch value will provide a high density of potentially active nucleation sites but still allow for the development of the thermal boundary layer thus not inhibiting the activation of neighboring spots. The size of (super)hydrophobic spots appears not to have a major influence on the boiling performance when using the optimal spot pitch. The developed superbiphilic surfaces increase the CHF and provide greatly enhanced heat transfer coefficients especially at medium and high heat fluxes, making them suitable especially for high-heat-flux applications.

• Language: English
• Keywords: heat transfer, pool boiling, nucleate boiling, biphilic surfaces, surface engineering, critical heat flux, surface functionalization, heat transfer enhancement
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2020
• Number of pages: 13 str.
• Numbering: Vol. 161, art. 120265
• PID: 20.500.12556/RUL-118090
• UDC: 536.24(045)
• ISSN on article: 0017-9310
• DOI: 10.1016/j.ijheatmasstransfer.2020.120265
• COBISS.SI-ID: 25544963
• Publication date in RUL: 19.08.2020

Record is a part of a journal

• Title: International journal of heat and mass transfer
• Shortened title: Int. j. heat mass transfer
• Publisher: Elsevier
• ISSN: 0017-9310
• COBISS.SI-ID: 3064335

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: prenos toplote, vrenje v bazenu, mehurčkasto vrenje, bifilne površine, inženiring površin, kritični toplotni tok, funkcionalizacija površin, izboljšanje prenosa toplote

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0223
• Name: Prenos toplote in snovi

• Funder: ARRS - Slovenian Research Agency
• Project number: J2-1741
• Name: Lasersko mikro in nanostrukturiranje za razvoj biomimetičnih kovinskih površin z edinstvenimi lastnostmi (LaMiNaS)