{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/105048"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/105048","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Enhanced phase change heat transfer through advanced fabrication techniques","abstract":"Phase change heat transfer is an essential phenomenon occurring both in nature and in our daily lives. The natural abundance along high latent heat makes water the most widely used fluid for several applications. Industries involving thermoelectric power generation, filtration, desalination, and HVAC&R (Heating, Ventilation, Air Conditioning and Refrigeration) systems utilize water as the working fluid. As a result, these industrial applications are susceptible to water phase change during operations. Heat transfer during vapor to liquid phase change or condensation is a critical industrial operation, determining the efficiency and costs of several processes. It is well established that dropwise condensation of water vapor has 10 – 20 times higher heat transfer compared to filmwise condensation. Dropwise condensation is promoted by hydrophobic surfaces, characterized with intrinsic advancing contact angles (CA) greater than 90° as against filmwise condensation on hydrophilic (CA < 90°) surfaces. With the advancement of micro-nanofabrication over the past three decades, novel ultra-low adhesion superhydrophobic (CA > 150°) surfaces have been developed through the combination of surface structuring and chemical functionalization. Recently, researchers have observed that when microdroplets (~10 – 100 μm) condense and coalesce on an ultra-low adhesion structured surface, the resulting excess surface energy causes the droplet to jump out of the surface against gravity. The removal of coalesced condensate droplets leads to rapid clearing of the condensing surface, resulting in higher nucleation rates. Such jumping-droplet based condensation has been shown to further enhance heat transfer coefficient by 30% when compared to classical dropwise condensation. This phenomenon has brought significant attention to fabricating superhydrophobic nanostructured surfaces to achieve spontaneous droplet removal for several applications including self-cleaning, thermal diodes, anti-icing, vapor chambers, electrostatic energy harvesting, and condensation heat transfer enhancement. In addition to enhanced heat transfer applications due to condensation, researchers have also investigated superhydrophobicity itself using various materials, structures, and non-polar coating techniques for versatile applications. The studies herein mainly focus on gaining fundamental understanding of water vapor nucleation on intrinsically designed surfaces, controlling and developing different wettability patterns. From developing facile fabrication methods, to providing design guidelines for optimizing wetting characteristics, the work herein leads to rational design and development of micro and nanoengineered surfaces for enhanced phase change heat transfer, elucidating their versatility for a plethora of energy related applications.","abstract_html":"Phase change heat transfer is an essential phenomenon occurring both in nature and in our daily lives. The natural abundance along high latent heat makes water the most widely used fluid for several applications. Industries involving thermoelectric power generation, filtration, desalination, and HVAC&amp;R (Heating, Ventilation, Air Conditioning and Refrigeration) systems utilize water as the working fluid. As a result, these industrial applications are susceptible to water phase change during operations. Heat transfer during vapor to liquid phase change or condensation is a critical industrial operation, determining the efficiency and costs of several processes. It is well established that dropwise condensation of water vapor has 10 – 20 times higher heat transfer compared to filmwise condensation. Dropwise condensation is promoted by hydrophobic surfaces, characterized with intrinsic advancing contact angles (CA) greater than 90° as against filmwise condensation on hydrophilic (CA &lt; 90°) surfaces. With the advancement of micro-nanofabrication over the past three decades, novel ultra-low adhesion superhydrophobic (CA &gt; 150°) surfaces have been developed through the combination of surface structuring and chemical functionalization. Recently, researchers have observed that when microdroplets (~10 – 100 μm) condense and coalesce on an ultra-low adhesion structured surface, the resulting excess surface energy causes the droplet to jump out of the surface against gravity. The removal of coalesced condensate droplets leads to rapid clearing of the condensing surface, resulting in higher nucleation rates. Such jumping-droplet based condensation has been shown to further enhance heat transfer coefficient by 30% when compared to classical dropwise condensation. This phenomenon has brought significant attention to fabricating superhydrophobic nanostructured surfaces to achieve spontaneous droplet removal for several applications including self-cleaning, thermal diodes, anti-icing, vapor chambers, electrostatic energy harvesting, and condensation heat transfer enhancement. In addition to enhanced heat transfer applications due to condensation, researchers have also investigated superhydrophobicity itself using various materials, structures, and non-polar coating techniques for versatile applications. The studies herein mainly focus on gaining fundamental understanding of water vapor nucleation on intrinsically designed surfaces, controlling and developing different wettability patterns. From developing facile fabrication methods, to providing design guidelines for optimizing wetting characteristics, the work herein leads to rational design and development of micro and nanoengineered surfaces for enhanced phase change heat transfer, elucidating their versatility for a plethora of energy related applications.","abstract_has_math":false,"creators":["Kim, Moonkyung"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Miljkovic, Nenad","Jacobi, Anthony M.","Ferreira, Placid M.","Braun, Paul V."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-08-23T20:35:59Z","date_published":"2019-08-23T20:35:59Z","updated_at":"2026-07-22T22:24:44Z","subjects":["Phase change, Heat transfer, Fabrication"],"languages":["en"],"rights":["© 2019 Moon-Kyung Kim"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/105048","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Miljkovic, Nenad","Jacobi, Anthony M.","Ferreira, Placid M.","Braun, Paul V."]},{"key":"dc:creator","label":"Author","values":["Kim, Moonkyung"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-08-23T20:35:59Z","2021-08-24T09:15:24Z","2019-04-17","2019-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Phase change, Heat transfer, Fabrication"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["© 2019 Moon-Kyung Kim"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/105048"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Phase change heat transfer is an essential phenomenon occurring both in nature and in our daily lives. The natural abundance along high latent heat makes water the most widely used fluid for several applications. Industries involving thermoelectric power generation, filtration, desalination, and HVAC&R (Heating, Ventilation, Air Conditioning and Refrigeration) systems utilize water as the working fluid. As a result, these industrial applications are susceptible to water phase change during operations. Heat transfer during vapor to liquid phase change or condensation is a critical industrial operation, determining the efficiency and costs of several processes. It is well established that dropwise condensation of water vapor has 10 – 20 times higher heat transfer compared to filmwise condensation. Dropwise condensation is promoted by hydrophobic surfaces, characterized with intrinsic advancing contact angles (CA) greater than 90° as against filmwise condensation on hydrophilic (CA < 90°) surfaces. With the advancement of micro-nanofabrication over the past three decades, novel ultra-low adhesion superhydrophobic (CA > 150°) surfaces have been developed through the combination of surface structuring and chemical functionalization. Recently, researchers have observed that when microdroplets (~10 – 100 μm) condense and coalesce on an ultra-low adhesion structured surface, the resulting excess surface energy causes the droplet to jump out of the surface against gravity. The removal of coalesced condensate droplets leads to rapid clearing of the condensing surface, resulting in higher nucleation rates. Such jumping-droplet based condensation has been shown to further enhance heat transfer coefficient by 30% when compared to classical dropwise condensation. This phenomenon has brought significant attention to fabricating superhydrophobic nanostructured surfaces to achieve spontaneous droplet removal for several applications including self-cleaning, thermal diodes, anti-icing, vapor chambers, electrostatic energy harvesting, and condensation heat transfer enhancement. In addition to enhanced heat transfer applications due to condensation, researchers have also investigated superhydrophobicity itself using various materials, structures, and non-polar coating techniques for versatile applications. The studies herein mainly focus on gaining fundamental understanding of water vapor nucleation on intrinsically designed surfaces, controlling and developing different wettability patterns. From developing facile fabrication methods, to providing design guidelines for optimizing wetting characteristics, the work herein leads to rational design and development of micro and nanoengineered surfaces for enhanced phase change heat transfer, elucidating their versatility for a plethora of energy related applications.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-05-01","The student, Moonkyung Kim, accepted the attached license on 2019-04-17 at 10:31.","The student, Moonkyung Kim, submitted this Dissertation for approval on 2019-04-17 at 10:31.","This Dissertation was approved for publication on 2019-04-17 at 11:39.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13702 on 2019-08-22 at 15:07:05","Made available in DSpace on 2019-08-23T20:35:59Z (GMT). No. of bitstreams: 2 KIM-DISSERTATION-2019.pdf: 5338950 bytes, checksum: 683423fd3829297fdcbf07339610d160 (MD5) LICENSE.txt: 4210 bytes, checksum: 90da4a63d3015fb429b62350f33887f9 (MD5) Previous issue date: 2019-04-17","Embargo set by: Seth Robbins for item 112167 Lift date: 2021-08-23T20:36:18Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","U of I Only Restriction Lifted for Item 112167 on 2021-08-24T09:15:24Z."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Enhanced phase change heat transfer through advanced fabrication techniques"]}]}],"canonical_facts":{"dc:contributor":["Miljkovic, Nenad","Jacobi, Anthony M.","Ferreira, Placid M.","Braun, Paul V."],"dc:creator":["Kim, Moonkyung"],"dc:date":["2019-08-23T20:35:59Z","2021-08-24T09:15:24Z","2019-04-17","2019-05"],"dc:description":["Phase change heat transfer is an essential phenomenon occurring both in nature and in our daily lives. The natural abundance along high latent heat makes water the most widely used fluid for several applications. Industries involving thermoelectric power generation, filtration, desalination, and HVAC&R (Heating, Ventilation, Air Conditioning and Refrigeration) systems utilize water as the working fluid. As a result, these industrial applications are susceptible to water phase change during operations. Heat transfer during vapor to liquid phase change or condensation is a critical industrial operation, determining the efficiency and costs of several processes. It is well established that dropwise condensation of water vapor has 10 – 20 times higher heat transfer compared to filmwise condensation. Dropwise condensation is promoted by hydrophobic surfaces, characterized with intrinsic advancing contact angles (CA) greater than 90° as against filmwise condensation on hydrophilic (CA < 90°) surfaces. With the advancement of micro-nanofabrication over the past three decades, novel ultra-low adhesion superhydrophobic (CA > 150°) surfaces have been developed through the combination of surface structuring and chemical functionalization. Recently, researchers have observed that when microdroplets (~10 – 100 μm) condense and coalesce on an ultra-low adhesion structured surface, the resulting excess surface energy causes the droplet to jump out of the surface against gravity. The removal of coalesced condensate droplets leads to rapid clearing of the condensing surface, resulting in higher nucleation rates. Such jumping-droplet based condensation has been shown to further enhance heat transfer coefficient by 30% when compared to classical dropwise condensation. This phenomenon has brought significant attention to fabricating superhydrophobic nanostructured surfaces to achieve spontaneous droplet removal for several applications including self-cleaning, thermal diodes, anti-icing, vapor chambers, electrostatic energy harvesting, and condensation heat transfer enhancement. In addition to enhanced heat transfer applications due to condensation, researchers have also investigated superhydrophobicity itself using various materials, structures, and non-polar coating techniques for versatile applications. The studies herein mainly focus on gaining fundamental understanding of water vapor nucleation on intrinsically designed surfaces, controlling and developing different wettability patterns. From developing facile fabrication methods, to providing design guidelines for optimizing wetting characteristics, the work herein leads to rational design and development of micro and nanoengineered surfaces for enhanced phase change heat transfer, elucidating their versatility for a plethora of energy related applications.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-05-01","The student, Moonkyung Kim, accepted the attached license on 2019-04-17 at 10:31.","The student, Moonkyung Kim, submitted this Dissertation for approval on 2019-04-17 at 10:31.","This Dissertation was approved for publication on 2019-04-17 at 11:39.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13702 on 2019-08-22 at 15:07:05","Made available in DSpace on 2019-08-23T20:35:59Z (GMT). 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