{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/115592"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/115592","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Enhancement of heat transfer and anti-scaling capabilities for pool boiling","abstract":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-05-01","abstract_html":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-05-01","abstract_has_math":false,"creators":["Zhang, Yuheng"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Wang, Sophie","Wang, Xinlei","Miljkovic, Nenad","Feng, Jie"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-05","date_published":"2022-05","updated_at":"2026-07-22T22:24:54Z","subjects":["Pool Boiling","Critical Heat Flux","Scaling","Fouling","Heat Transfer","Enhancement"],"languages":["en","eng"],"rights":["Copyright 2022 Yuheng Zhang"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/115592","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Wang, Sophie","Wang, Xinlei","Miljkovic, Nenad","Feng, Jie"]},{"key":"dc:creator","label":"Author","values":["Zhang, Yuheng"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-05","2022-04-22"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"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":["Pool Boiling","Critical Heat Flux","Scaling","Fouling","Heat Transfer","Enhancement"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2022 Yuheng Zhang"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/115592"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-05-01","The student, Yuheng Zhang, accepted the attached license on 2022-04-20 at 16:29.","The student, Yuheng Zhang, submitted this Dissertation for approval on 2022-04-21 at 15:02.","This Dissertation was approved for publication on 2022-04-22 at 11:18.","DSpace SAF Submission Ingestion Package generated from Vireo submission #17861 on 2022-11-11 at 12:11:37","Nucleate boiling is one of the most efficient modes of heat transfer. Durable enhancement of the boiling performance has always been a great interest in many applications. In this work, we extend the research on a non-coating-based methodology that aims to enhance the nucleate boiling heat transfer and antiscaling capabilities by harnessing the hydrodynamics and capillaries induced in the boiling process. A new vapor management approach is proposed to enhance convection and stabilize the vapor flow emitted from a boiling surface with robust shroud structures – 1. Straight, tubular vapor shrouds are found to improve the stability of the liquid feeding and increase the critical heat flux (CHF). Near the CHF, the flow structure inside the vapor blanket is visualized, showing liquid entrainment passing into the vapor blanket and splashing onto the heated surface, which provides an answer to the problem of liquid feeding mechanism on a small and non-wicking surface. Momentum and energy analysis shows the CHF scales with the resulting maximum liquid flow rate by the shroud structure; 2. Compact shrouds with curved shapes are shown to enhance the heat transfer coefficient in nucleate boiling by increasing bubble expansion, promoting bubble coalescence, and enhancing thin-film evaporation. Characteristics of the liquid-vapor two-phase flow inside the shroud is analyzed. The resulted liquid feeding mechanism near CHF is discussed, and an equation based on scaling analysis is derived to predict the effect of shroud on heat transfer The characteristics of scale deposition in nucleate boiling with high salinity aqueous solution is also experimentally investigated. A surface design with micro-machined grooves on a polished stainless-steel substrate demonstrates a strong suppression effect on scale nucleation. Different groove depth and spacing designs are examined. The effect on heat transfer, bubble nucleation and scale morphology characteristics are analyzed. It is shown that grooves with an appropriate depth can enhance bubble nucleation while reducing scale deposition rate, whereas on the smooth substrate, bubble nucleation can only cause scale deposition rate to increase. The similarity between the anti-scaling effect of grooves and re-entrant fins is analyzed, which indicates that the suppressed scale deposition on grooved surfaces is mainly contributed by 1. the cooling effect due to enhanced bubble nucleation, and 2. the reduced surface dryout due to well preserved liquid meniscus. This work expands the understanding of three key mechanisms in nucleate boiling – 1. film evaporation, 2. liquid feeding, and 3. deposition of solids. Robust control methodologies for enhancing film evaporation, increasing liquid feeding stability, and reducing scale deposition are proposed and examined. The demonstrated method for direct visualization of the flow structure inside a vapor blanket also opens new opportunities for studying the liquid feeding mechanism in nucleate boiling near the critical heat flux."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Enhancement of heat transfer and anti-scaling capabilities for pool boiling"]}]}],"canonical_facts":{"dc:contributor":["Wang, Sophie","Wang, Xinlei","Miljkovic, Nenad","Feng, Jie"],"dc:creator":["Zhang, Yuheng"],"dc:date":["2022-05","2022-04-22"],"dc:description":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-05-01","The student, Yuheng Zhang, accepted the attached license on 2022-04-20 at 16:29.","The student, Yuheng Zhang, submitted this Dissertation for approval on 2022-04-21 at 15:02.","This Dissertation was approved for publication on 2022-04-22 at 11:18.","DSpace SAF Submission Ingestion Package generated from Vireo submission #17861 on 2022-11-11 at 12:11:37","Nucleate boiling is one of the most efficient modes of heat transfer. Durable enhancement of the boiling performance has always been a great interest in many applications. In this work, we extend the research on a non-coating-based methodology that aims to enhance the nucleate boiling heat transfer and antiscaling capabilities by harnessing the hydrodynamics and capillaries induced in the boiling process. A new vapor management approach is proposed to enhance convection and stabilize the vapor flow emitted from a boiling surface with robust shroud structures – 1. Straight, tubular vapor shrouds are found to improve the stability of the liquid feeding and increase the critical heat flux (CHF). Near the CHF, the flow structure inside the vapor blanket is visualized, showing liquid entrainment passing into the vapor blanket and splashing onto the heated surface, which provides an answer to the problem of liquid feeding mechanism on a small and non-wicking surface. Momentum and energy analysis shows the CHF scales with the resulting maximum liquid flow rate by the shroud structure; 2. Compact shrouds with curved shapes are shown to enhance the heat transfer coefficient in nucleate boiling by increasing bubble expansion, promoting bubble coalescence, and enhancing thin-film evaporation. Characteristics of the liquid-vapor two-phase flow inside the shroud is analyzed. The resulted liquid feeding mechanism near CHF is discussed, and an equation based on scaling analysis is derived to predict the effect of shroud on heat transfer The characteristics of scale deposition in nucleate boiling with high salinity aqueous solution is also experimentally investigated. A surface design with micro-machined grooves on a polished stainless-steel substrate demonstrates a strong suppression effect on scale nucleation. Different groove depth and spacing designs are examined. The effect on heat transfer, bubble nucleation and scale morphology characteristics are analyzed. It is shown that grooves with an appropriate depth can enhance bubble nucleation while reducing scale deposition rate, whereas on the smooth substrate, bubble nucleation can only cause scale deposition rate to increase. The similarity between the anti-scaling effect of grooves and re-entrant fins is analyzed, which indicates that the suppressed scale deposition on grooved surfaces is mainly contributed by 1. the cooling effect due to enhanced bubble nucleation, and 2. the reduced surface dryout due to well preserved liquid meniscus. This work expands the understanding of three key mechanisms in nucleate boiling – 1. film evaporation, 2. liquid feeding, and 3. deposition of solids. Robust control methodologies for enhancing film evaporation, increasing liquid feeding stability, and reducing scale deposition are proposed and examined. The demonstrated method for direct visualization of the flow structure inside a vapor blanket also opens new opportunities for studying the liquid feeding mechanism in nucleate boiling near the critical heat flux."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/115592"],"dc:language":["en","eng"],"dc:rights":["Copyright 2022 Yuheng Zhang"],"dc:subject":["Pool Boiling","Critical Heat Flux","Scaling","Fouling","Heat Transfer","Enhancement"],"dc:title":["Enhancement of heat transfer and anti-scaling capabilities for pool boiling"],"dc:type":["text","Thesis"],"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":"2026-07-22T22:24:54Z"}