Biphilic surfaces for phase change heat transfer enhancement; design, fabrication and applications

Improving heat transfer performance in power generation, heating, electronics cooling, and refrigeration has great environmental and economic impact. Given that the highest attainable heat transfer fluxes are usually associated with fluid which undergo phase change from liquid to vapor or vapor to liquid, improving the phase change heat transfer mechanism by using specific surface designs and wettabilities has much interest. Biphilic or hybrid wettability surfaces, surfaces comprised of patterns having distinct spatial wettability, have shown promise to help enhance phase change heat transfer by controlling the distribution of liquid and vapor at the surface and controlling its shedding dynamics. This thesis explores biphilic surfaces for improving phase change heat transfer during condensation, implements novel methods to scale-up fabrication, and tests biphilic surfaces in an environmental humidity water collection setup. The research reviews existing designs, manufacturing methods, and applications of biphilic surfaces for phase change heat transfer enhancement applications. It analyzes the influence of biphilic surface features on phase change phenomena such as condensation and boiling. Critical analysis is conducted on particular manufacturing techniques with a focus on economic and environmental costs and benefits. The analysis outlines the two main reasons hindering the adaption of biphilic surfaces in industrial applications, mainly reliability and scalability of the fabrication techniques. An improved fabrication method for creating biphilic surfaces is proposed, with a focus on scalability, cost-effectiveness and environmental friendliness. A custom-made setup is designed and built to create biphilic surfaces on aluminum fin stock rolls. Two types of biphilic surfaces were successfully fabricated using the setup. A hydrophilic \ superhydrophilic surface and a hydrophobic\ hydrophilic surface were fabricated at rate of 120 sq. in/ and 60 sq. in/hour consecutively. Our method speeds up previously outlined fabrication rates by factors of 5 to 10, opening the door for large scale fabrication of biphilic surfaces. Finally, aluminum biphilic samples having different wettability patterns and wettability contrasts were manufactured and tested under environmental humidity water collection. The tests shown that biphilic surfaces can achieve up to 15% improvement on water collection rate compared to the best non-biphilic surfaces. These results encourage the pursuit of further utilization of biphilic surfaces in phase change heat transfer applications.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Linjawi, Majid Tareq A

Contributors dc:contributor

• Miljkovic, Nenad
• Wang, Pingfeng
• Wang, Sophie
• Nawaz, Kashif

• Biphilic Surface
• Phase Change Heat Transfer
• Roll-to-roll Fabrication
• Water Harvesting
• Condensation\

Statement dc:rights

• Copyright 2024 Majid Linjawi

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/125811

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F125811