Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluids
Autor(a) principal: | |
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Data de Publicação: | 2020 |
Outros Autores: | , , |
Tipo de documento: | Artigo de conferência |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1615/TFEC2020.boi.032136 http://hdl.handle.net/11449/205210 |
Resumo: | One promising way to enhance the heat transfer coefficient (HTC) and the critical heat flux (CHF) is modifying the heating surface morphology by using machining techniques, coating, and chemical processes. Microstructured surfaces, i.e., surfaces with the presence of micro-pillars on the surface, provide small perturbations in the liquid, affecting the vapor bubbles dynamic. These structures increase the heating surface area and change the fluid flow. Micro-fins can have different shapes and sizes and can be arranged in different patterns to improve heat transfer. This study aims to evaluate experimentally the thermal performance of different micro-fin surfaces by using HFE-7100 as working fluid. The square-micro pillar arrays were etched on a plain copper surface through the micro-milling process. Squares micro-fins of different length scales (i.e., height and side length) were uniformly spaced on the plain copper surface. The inter-fin space had the same value, 250 μm, for all surfaces in order to control the effective roughness, Reff, defined as the ratio of the area in contact with the liquid to the projected area. Micro-fin surfaces intensify the HTC as compared to the plain surface and the number of fins is the main factor for the HTC enhancement; if the number of micro-fins is constant, the larger the effective roughness the higher the heat transfer performance. Additionally, the capillary-wicking ability increases and it also improves the HTC and the dryout heat flux due to the prevention of hotspots in the micro-fin surface. Thus, the surface thermal behavior is a function of the surface morphology and its surface capillary wicking. |
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Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluidsEffective roughnessHeat transfer coefficientHFE-7100Micro-pillarsPool boilingOne promising way to enhance the heat transfer coefficient (HTC) and the critical heat flux (CHF) is modifying the heating surface morphology by using machining techniques, coating, and chemical processes. Microstructured surfaces, i.e., surfaces with the presence of micro-pillars on the surface, provide small perturbations in the liquid, affecting the vapor bubbles dynamic. These structures increase the heating surface area and change the fluid flow. Micro-fins can have different shapes and sizes and can be arranged in different patterns to improve heat transfer. This study aims to evaluate experimentally the thermal performance of different micro-fin surfaces by using HFE-7100 as working fluid. The square-micro pillar arrays were etched on a plain copper surface through the micro-milling process. Squares micro-fins of different length scales (i.e., height and side length) were uniformly spaced on the plain copper surface. The inter-fin space had the same value, 250 μm, for all surfaces in order to control the effective roughness, Reff, defined as the ratio of the area in contact with the liquid to the projected area. Micro-fin surfaces intensify the HTC as compared to the plain surface and the number of fins is the main factor for the HTC enhancement; if the number of micro-fins is constant, the larger the effective roughness the higher the heat transfer performance. Additionally, the capillary-wicking ability increases and it also improves the HTC and the dryout heat flux due to the prevention of hotspots in the micro-fin surface. Thus, the surface thermal behavior is a function of the surface morphology and its surface capillary wicking.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNESP – São Paulo State University School of Engineering Post-Graduation Program in Mechanical Engineering, Av. Brasil, 56UNESP – São Paulo State University Campus of São João da Boa VistaUNESP – São Paulo State University School of Engineering Post-Graduation Program in Mechanical Engineering, Av. Brasil, 56UNESP – São Paulo State University Campus of São João da Boa VistaCNPq: 458702/2014-5Universidade Estadual Paulista (Unesp)Kiyomura, Igor Seicho [UNESP]Nunes, Jéssica Martha [UNESP]Rodrigues de Souza, Reinaldo [UNESP]Cardoso, Elaine Maria [UNESP]2021-06-25T10:11:39Z2021-06-25T10:11:39Z2020-01-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/conferenceObject15-23http://dx.doi.org/10.1615/TFEC2020.boi.032136Proceedings of the Thermal and Fluids Engineering Summer Conference, v. 2020-April, p. 15-23.2379-1748http://hdl.handle.net/11449/20521010.1615/TFEC2020.boi.0321362-s2.0-85091382305Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengProceedings of the Thermal and Fluids Engineering Summer Conferenceinfo:eu-repo/semantics/openAccess2021-10-23T12:10:31Zoai:repositorio.unesp.br:11449/205210Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T22:09:57.078421Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluids |
title |
Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluids |
spellingShingle |
Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluids Kiyomura, Igor Seicho [UNESP] Effective roughness Heat transfer coefficient HFE-7100 Micro-pillars Pool boiling |
title_short |
Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluids |
title_full |
Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluids |
title_fullStr |
Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluids |
title_full_unstemmed |
Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluids |
title_sort |
Pool boiling heat transfer enhancement using micro-fin surfaces and dielectric fluids |
author |
Kiyomura, Igor Seicho [UNESP] |
author_facet |
Kiyomura, Igor Seicho [UNESP] Nunes, Jéssica Martha [UNESP] Rodrigues de Souza, Reinaldo [UNESP] Cardoso, Elaine Maria [UNESP] |
author_role |
author |
author2 |
Nunes, Jéssica Martha [UNESP] Rodrigues de Souza, Reinaldo [UNESP] Cardoso, Elaine Maria [UNESP] |
author2_role |
author author author |
dc.contributor.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) |
dc.contributor.author.fl_str_mv |
Kiyomura, Igor Seicho [UNESP] Nunes, Jéssica Martha [UNESP] Rodrigues de Souza, Reinaldo [UNESP] Cardoso, Elaine Maria [UNESP] |
dc.subject.por.fl_str_mv |
Effective roughness Heat transfer coefficient HFE-7100 Micro-pillars Pool boiling |
topic |
Effective roughness Heat transfer coefficient HFE-7100 Micro-pillars Pool boiling |
description |
One promising way to enhance the heat transfer coefficient (HTC) and the critical heat flux (CHF) is modifying the heating surface morphology by using machining techniques, coating, and chemical processes. Microstructured surfaces, i.e., surfaces with the presence of micro-pillars on the surface, provide small perturbations in the liquid, affecting the vapor bubbles dynamic. These structures increase the heating surface area and change the fluid flow. Micro-fins can have different shapes and sizes and can be arranged in different patterns to improve heat transfer. This study aims to evaluate experimentally the thermal performance of different micro-fin surfaces by using HFE-7100 as working fluid. The square-micro pillar arrays were etched on a plain copper surface through the micro-milling process. Squares micro-fins of different length scales (i.e., height and side length) were uniformly spaced on the plain copper surface. The inter-fin space had the same value, 250 μm, for all surfaces in order to control the effective roughness, Reff, defined as the ratio of the area in contact with the liquid to the projected area. Micro-fin surfaces intensify the HTC as compared to the plain surface and the number of fins is the main factor for the HTC enhancement; if the number of micro-fins is constant, the larger the effective roughness the higher the heat transfer performance. Additionally, the capillary-wicking ability increases and it also improves the HTC and the dryout heat flux due to the prevention of hotspots in the micro-fin surface. Thus, the surface thermal behavior is a function of the surface morphology and its surface capillary wicking. |
publishDate |
2020 |
dc.date.none.fl_str_mv |
2020-01-01 2021-06-25T10:11:39Z 2021-06-25T10:11:39Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/conferenceObject |
format |
conferenceObject |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1615/TFEC2020.boi.032136 Proceedings of the Thermal and Fluids Engineering Summer Conference, v. 2020-April, p. 15-23. 2379-1748 http://hdl.handle.net/11449/205210 10.1615/TFEC2020.boi.032136 2-s2.0-85091382305 |
url |
http://dx.doi.org/10.1615/TFEC2020.boi.032136 http://hdl.handle.net/11449/205210 |
identifier_str_mv |
Proceedings of the Thermal and Fluids Engineering Summer Conference, v. 2020-April, p. 15-23. 2379-1748 10.1615/TFEC2020.boi.032136 2-s2.0-85091382305 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Proceedings of the Thermal and Fluids Engineering Summer Conference |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
15-23 |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
_version_ |
1808129398981787648 |