{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/106352"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/106352","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Liquid-infused slippery surfaces for air-conditioning and refrigeration applications","abstract":"Liquid-infused surfaces have drawn a lot of attention due to their excellent water repellency. A method is presented for creating a durable liquid-infused surface (LISs) on aluminum surfaces to minimize the water retention and enhance thermal-hydraulic performance for air-conditioning and refrigeration (AC&R) applications. The results demonstrate that the LISs has a sliding angle smaller than 5˚ and reduces the water retention ratio after defrosting by more than 75% compared to the baseline specimen. A delay of ice formation is also observed. These LISs can effectively drain condensate, retard frost formation, and reduce frost meltwater retention. Water droplet configuration on the LISs is explored. Droplets float on the surface and are surrounded by an annular ridge of lubricant. The excess surface energy released during the coalescence drives the droplets to move on the horizontal LISs and induces droplet jumping on a superhydrophobic surface. The changes in Gibbs energy (ΔG) of the condensation at the oil-air and oil-solid interfaces are also investigated to understand better the onset of condensation and thus lead to enhanced nucleation. Water prefers condensing at a higher relative humidity environment and on a more wettable substrate due to less ΔG at a metastable equilibrium. The onset of condensation can occur at the oil-air interface or the oil-solid interface depending on the relative humidity, the substrate wettability, and the water solubility. The longevity of surfaces is examined from periodic frosting and defrosting experiments. The oxalic acid-anodized LISs with nanostructures keep the water repellency after 60 frosting and defrosting cycles. The sulfuric acid-anodized LISs with hierarchical structures is not capable of locking the lubricant on the surface, so the performance deteriorates with increasing cycles. The hierarchical textured substrate has a smaller capillary pressure and a capillary pressure gradient, which causes an unstable lubricant layer and thus accelerates the oil depletion. Therefore, a substrate with uniform nanostructures is recommended for an LIS. A plain-fin-and-tube heat exchanger with LISs aluminum fins and the other heat exchanger with hydrophilic fins are built with the same fin-and-tube configuration. The effect of the liquid-infused fin surface design on the heat transfer and thermal-hydraulic performance is quantified experimentally under dry and wet conditions in a closed-loop wind tunnel. Surface wettability has more impact on the air-side pressure drop than it does on the heat transfer coefficient. Two heat exchangers have a comparable heat transfer coefficient under wet conditions, but the pressure drop of the slippery prototype is decreased by up to 27% due to better water drainage behavior than that of a hydrophilic baseline. Overall, the liquid-infused heat transfer surfaces show promise for AC&R applications.","abstract_html":"Liquid-infused surfaces have drawn a lot of attention due to their excellent water repellency. A method is presented for creating a durable liquid-infused surface (LISs) on aluminum surfaces to minimize the water retention and enhance thermal-hydraulic performance for air-conditioning and refrigeration (AC&R) applications. The results demonstrate that the LISs has a sliding angle smaller than 5˚ and reduces the water retention ratio after defrosting by more than 75% compared to the baseline specimen. A delay of ice formation is also observed. These LISs can effectively drain condensate, retard frost formation, and reduce frost meltwater retention. Water droplet configuration on the LISs is explored. Droplets float on the surface and are surrounded by an annular ridge of lubricant. The excess surface energy released during the coalescence drives the droplets to move on the horizontal LISs and induces droplet jumping on a superhydrophobic surface. The changes in Gibbs energy (ΔG) of the condensation at the oil-air and oil-solid interfaces are also investigated to understand better the onset of condensation and thus lead to enhanced nucleation. Water prefers condensing at a higher relative humidity environment and on a more wettable substrate due to less ΔG at a metastable equilibrium. The onset of condensation can occur at the oil-air interface or the oil-solid interface depending on the relative humidity, the substrate wettability, and the water solubility. The longevity of surfaces is examined from periodic frosting and defrosting experiments. The oxalic acid-anodized LISs with nanostructures keep the water repellency after 60 frosting and defrosting cycles. The sulfuric acid-anodized LISs with hierarchical structures is not capable of locking the lubricant on the surface, so the performance deteriorates with increasing cycles. The hierarchical textured substrate has a smaller capillary pressure and a capillary pressure gradient, which causes an unstable lubricant layer and thus accelerates the oil depletion. Therefore, a substrate with uniform nanostructures is recommended for an LIS. A plain-fin-and-tube heat exchanger with LISs aluminum fins and the other heat exchanger with hydrophilic fins are built with the same fin-and-tube configuration. The effect of the liquid-infused fin surface design on the heat transfer and thermal-hydraulic performance is quantified experimentally under dry and wet conditions in a closed-loop wind tunnel. Surface wettability has more impact on the air-side pressure drop than it does on the heat transfer coefficient. Two heat exchangers have a comparable heat transfer coefficient under wet conditions, but the pressure drop of the slippery prototype is decreased by up to 27% due to better water drainage behavior than that of a hydrophilic baseline. Overall, the liquid-infused heat transfer surfaces show promise for AC&R applications.","abstract_has_math":false,"creators":["Yu, Rong"],"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","Dutton, Craig","Jacobi, Anthony M.","Hrnjak, Predrag S."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-03-02T22:12:20Z","date_published":"2020-03-02T22:12:20Z","updated_at":"2026-07-22T22:24:45Z","subjects":["Liquid-infused surface","Surface wettability","Heat transfer","Droplet mobility","Air-conditioning and refrigeration applications","Water drainage","Air-side pressure drop","Surface modification","Wettability management","Heat exchanger performance","Condensation","Frosting and defrosting"],"languages":["en"],"rights":["Copyright 2019 Rong Yu"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/106352","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Miljkovic, Nenad","Dutton, Craig","Jacobi, Anthony M.","Hrnjak, Predrag S."]},{"key":"dc:creator","label":"Author","values":["Yu, Rong"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-03-02T22:12:20Z","2022-03-03T10:15:25Z","2019-11-25","2019-12"]},{"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":["Liquid-infused surface","Surface wettability","Heat transfer","Droplet mobility","Air-conditioning and refrigeration applications","Water drainage","Air-side pressure drop","Surface modification","Wettability management","Heat exchanger performance","Condensation","Frosting and defrosting"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2019 Rong Yu"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/106352"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Liquid-infused surfaces have drawn a lot of attention due to their excellent water repellency. A method is presented for creating a durable liquid-infused surface (LISs) on aluminum surfaces to minimize the water retention and enhance thermal-hydraulic performance for air-conditioning and refrigeration (AC&R) applications. The results demonstrate that the LISs has a sliding angle smaller than 5˚ and reduces the water retention ratio after defrosting by more than 75% compared to the baseline specimen. A delay of ice formation is also observed. These LISs can effectively drain condensate, retard frost formation, and reduce frost meltwater retention. Water droplet configuration on the LISs is explored. Droplets float on the surface and are surrounded by an annular ridge of lubricant. The excess surface energy released during the coalescence drives the droplets to move on the horizontal LISs and induces droplet jumping on a superhydrophobic surface. The changes in Gibbs energy (ΔG) of the condensation at the oil-air and oil-solid interfaces are also investigated to understand better the onset of condensation and thus lead to enhanced nucleation. Water prefers condensing at a higher relative humidity environment and on a more wettable substrate due to less ΔG at a metastable equilibrium. The onset of condensation can occur at the oil-air interface or the oil-solid interface depending on the relative humidity, the substrate wettability, and the water solubility. The longevity of surfaces is examined from periodic frosting and defrosting experiments. The oxalic acid-anodized LISs with nanostructures keep the water repellency after 60 frosting and defrosting cycles. The sulfuric acid-anodized LISs with hierarchical structures is not capable of locking the lubricant on the surface, so the performance deteriorates with increasing cycles. The hierarchical textured substrate has a smaller capillary pressure and a capillary pressure gradient, which causes an unstable lubricant layer and thus accelerates the oil depletion. Therefore, a substrate with uniform nanostructures is recommended for an LIS. A plain-fin-and-tube heat exchanger with LISs aluminum fins and the other heat exchanger with hydrophilic fins are built with the same fin-and-tube configuration. The effect of the liquid-infused fin surface design on the heat transfer and thermal-hydraulic performance is quantified experimentally under dry and wet conditions in a closed-loop wind tunnel. Surface wettability has more impact on the air-side pressure drop than it does on the heat transfer coefficient. Two heat exchangers have a comparable heat transfer coefficient under wet conditions, but the pressure drop of the slippery prototype is decreased by up to 27% due to better water drainage behavior than that of a hydrophilic baseline. Overall, the liquid-infused heat transfer surfaces show promise for AC&R applications.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-12-01","The student, Rong Yu, accepted the attached license on 2019-11-20 at 21:15.","The student, Rong Yu, submitted this Dissertation for approval on 2019-11-20 at 21:30.","This Dissertation was approved for publication on 2019-11-25 at 09:51.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14576 on 2020-02-28 at 17:22:29","Made available in DSpace on 2020-03-02T22:12:20Z (GMT). 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A method is presented for creating a durable liquid-infused surface (LISs) on aluminum surfaces to minimize the water retention and enhance thermal-hydraulic performance for air-conditioning and refrigeration (AC&R) applications. The results demonstrate that the LISs has a sliding angle smaller than 5˚ and reduces the water retention ratio after defrosting by more than 75% compared to the baseline specimen. A delay of ice formation is also observed. These LISs can effectively drain condensate, retard frost formation, and reduce frost meltwater retention. Water droplet configuration on the LISs is explored. Droplets float on the surface and are surrounded by an annular ridge of lubricant. The excess surface energy released during the coalescence drives the droplets to move on the horizontal LISs and induces droplet jumping on a superhydrophobic surface. The changes in Gibbs energy (ΔG) of the condensation at the oil-air and oil-solid interfaces are also investigated to understand better the onset of condensation and thus lead to enhanced nucleation. Water prefers condensing at a higher relative humidity environment and on a more wettable substrate due to less ΔG at a metastable equilibrium. The onset of condensation can occur at the oil-air interface or the oil-solid interface depending on the relative humidity, the substrate wettability, and the water solubility. The longevity of surfaces is examined from periodic frosting and defrosting experiments. The oxalic acid-anodized LISs with nanostructures keep the water repellency after 60 frosting and defrosting cycles. The sulfuric acid-anodized LISs with hierarchical structures is not capable of locking the lubricant on the surface, so the performance deteriorates with increasing cycles. The hierarchical textured substrate has a smaller capillary pressure and a capillary pressure gradient, which causes an unstable lubricant layer and thus accelerates the oil depletion. Therefore, a substrate with uniform nanostructures is recommended for an LIS. A plain-fin-and-tube heat exchanger with LISs aluminum fins and the other heat exchanger with hydrophilic fins are built with the same fin-and-tube configuration. The effect of the liquid-infused fin surface design on the heat transfer and thermal-hydraulic performance is quantified experimentally under dry and wet conditions in a closed-loop wind tunnel. Surface wettability has more impact on the air-side pressure drop than it does on the heat transfer coefficient. Two heat exchangers have a comparable heat transfer coefficient under wet conditions, but the pressure drop of the slippery prototype is decreased by up to 27% due to better water drainage behavior than that of a hydrophilic baseline. Overall, the liquid-infused heat transfer surfaces show promise for AC&R applications.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-12-01","The student, Rong Yu, accepted the attached license on 2019-11-20 at 21:15.","The student, Rong Yu, submitted this Dissertation for approval on 2019-11-20 at 21:30.","This Dissertation was approved for publication on 2019-11-25 at 09:51.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14576 on 2020-02-28 at 17:22:29","Made available in DSpace on 2020-03-02T22:12:20Z (GMT). No. of bitstreams: 3 YU-DISSERTATION-2019.pdf: 5336225 bytes, checksum: d5cbff19343343f10edd2e061cb9392b (MD5) LICENSE.txt: 4204 bytes, checksum: 7d1c53a6b2c8d931e1624e4979e19943 (MD5) PROQUEST_LICENSE.txt: 4550 bytes, checksum: 055eaf6b90717c2c45592fa6a7b8b18c (MD5) Previous issue date: 2019-11-25","Embargo set by: Seth Robbins for item 113893 Lift date: 2022-03-02T22:12:26Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113893 Lift date: 2022-03-02T22:15:21Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 113893 Lift date: 2022-03-02T22:18:25Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","U of I Only Restriction Lifted for Item 113893 on 2022-03-03T10:15:25Z."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/106352"],"dc:language":["en"],"dc:rights":["Copyright 2019 Rong Yu"],"dc:subject":["Liquid-infused surface","Surface wettability","Heat transfer","Droplet mobility","Air-conditioning and refrigeration applications","Water drainage","Air-side pressure drop","Surface modification","Wettability management","Heat exchanger performance","Condensation","Frosting and defrosting"],"dc:title":["Liquid-infused slippery surfaces for air-conditioning and refrigeration applications"],"dc:type":["text"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:45Z"}