Influence of surface characteristics on pool boiling heat transfer
department or school: Applied Science, Faculty of
department or school: Engineering, School of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Xia, Yakang
issued: 2023-09-15T21:30:29Z
issued: 2023
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Pool boiling is a promising solution for meeting the heat dissipation requirements in high-heat-flux applications such as supercomputers, nuclear reactors, and laser generators. Surface characteristics greatly influence boiling heat transfer, which makes it crucial to understand their impact for enhanced heat transfer surface design. However, certain aspects of pool boiling, especially bubble behaviors and heat transfer with wettability contrast remain unclear. This thesis investigates the influence of surface wettability, textures, and orientation on pool boiling heat transfer using water as the working fluid. The research includes five steps. Firstly, thin-film heaters are fabricated to enable precise temperature measurements with an infrared camera. Microstructures are created on the boiling surface using laser ablation. Together with silanization grafting, different surfaces ranging from super-hydrophilic to super-hydrophobic are produced. Secondly, experimental studies are conducted focusing on observing injected air bubble formation and motion behaviors to understand the effects of surface wettability. Results demonstrate that surface wettability significantly influences bubble size and departure frequency, and bubbles spread to the super-hydrophobic region due to wettability contrast. Thirdly, pool boiling tests on different wetting surfaces show differences in bubble formation and departure. Nucleate boiling curves indicate that the heat transfer coefficient and critical heat flux generally increase as surface wettability transitions from super-hydrophobic to super-hydrophilic. The quantitative assessment of surface effects using surface-fluid factor confirms higher values for super-hydrophobic surfaces. For hydrophilic surfaces, the effect remains relatively constant over the nucleate boiling range, while hydrophobic surfaces show dependency on heat flux. These findings are consistent with boiling tests on a biphilic surface comprising super-hydrophobic and…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/85939
note: INFLUENCE OF SURFACE CHARACTERISTICS ON POOL BOILING HEAT TRANSFER by Yakang Xia M.Sc., Khalifa University of Science and Technology, UAE, 2016 B.Eng., China University of Petroleum (Beijing), China, 2014 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE COLLEGE OF GRADUATE STUDIES (Mechanical Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) September 2023 © Yakang Xia, 2023 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Influence of surface characteristics on pool boiling heat transfer submitted by Yakang Xia in partial fulfillment of the requirements of the degree of Doctor of Philosophy Examining Committee Dr. Sunny Ri Li, School of Engineering Supervisor Dr. Sina Kheirkhah, School of Engineering Supervisory Committee Member Dr. Vladan Prodanovic, University of British Columbia-Vancouver Supervisory Committee Member Dr. John Frostad, University of British Columbia-Vancouver University Examiner Dr. Hongwei Wu, University of Hertfordshire External Examiner iii Abstract Pool boiling is a promising solution for meeting the heat dissipation requirements in high-heat-flux applications such as supercomputers, nuclear reactors, and laser generators. Surface characteristics greatly influence boiling heat transfer, which makes it crucial to understand their impact for enhanced heat transfer surface design. However, certain aspects of pool boiling, especially bubble behaviors and heat transfer with wettability contrast remain unclear. This thesis investigates the influence of surface wettability, textures, and orientation on pool boiling heat transfer using water as the working fluid. The research includes five steps. Firstly, thin-film heaters are fabricated to ensure uniform heat flux and enable precise temperature measurements with an infrared camera. Microstructures are created on the …
has type: Thesis/Dissertation
date issued: 2023-11
is shown at: 10.14288/1.0435901
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Li, Ri
type: Text
identifier URI: http://hdl.handle.net/2429/85939