The effect of ambient pressure on the heat transfer of a water spray
Autor(a) principal: | |
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Data de Publicação: | 2019 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/1822/66264 |
Resumo: | The present work is aimed at quantifying the effects of ambient pressure in the heat transfer at single injections of a full cone spray over a hot metal surface. The experimental configuration is that of a spray impinging down perpendicularly onto a flat surface located at 55 mm inside an injection chamber. The experiments were conducted for prescribed initial wall temperatures ranging from single phase to local nucleate boiling and transition regimes of heat transfer. Ambient pressures ranged from atmospheric to 30 bar. The analysis is based on spatial resolved measurements of the instantaneous surface temperature during the injection period. The measurements are then processed in order to obtain estimates of the time-averaged values of the local heat flux. The overall cooling rate is also obtained by integrating the local values within the total area of the spray impact Results show that the amount of heat extracted by the impinging spray increases 3.4 times when ambient pressure is increased from atmospheric to 20 bar at the same superheating degree at the wall of 45 degrees C. This corresponds to an increase from 13.3% to 47.7% in the ratio between the actual cooling and the theoretical maximum cooling, defined here as cooling efficiency. This is a result of a better spreading of the liquid film at the wall, covering a larger footprint upon impact. Instantaneous peak heat flux is also increased, as a clear indication of the improved heat transfer between the impinging droplets and the wall.The work presented herein derives from a broader research program devised to develop a system for in cylinder cooling of internal combustion engines using high pressure water sprays produced by gasoline direct injectors. |
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The effect of ambient pressure on the heat transfer of a water spraySpray coolingTransient wall heat fluxHigh Ambient PressureScience & TechnologyThe present work is aimed at quantifying the effects of ambient pressure in the heat transfer at single injections of a full cone spray over a hot metal surface. The experimental configuration is that of a spray impinging down perpendicularly onto a flat surface located at 55 mm inside an injection chamber. The experiments were conducted for prescribed initial wall temperatures ranging from single phase to local nucleate boiling and transition regimes of heat transfer. Ambient pressures ranged from atmospheric to 30 bar. The analysis is based on spatial resolved measurements of the instantaneous surface temperature during the injection period. The measurements are then processed in order to obtain estimates of the time-averaged values of the local heat flux. The overall cooling rate is also obtained by integrating the local values within the total area of the spray impact Results show that the amount of heat extracted by the impinging spray increases 3.4 times when ambient pressure is increased from atmospheric to 20 bar at the same superheating degree at the wall of 45 degrees C. This corresponds to an increase from 13.3% to 47.7% in the ratio between the actual cooling and the theoretical maximum cooling, defined here as cooling efficiency. This is a result of a better spreading of the liquid film at the wall, covering a larger footprint upon impact. Instantaneous peak heat flux is also increased, as a clear indication of the improved heat transfer between the impinging droplets and the wall.The work presented herein derives from a broader research program devised to develop a system for in cylinder cooling of internal combustion engines using high pressure water sprays produced by gasoline direct injectors.The authors would like to acknowledge LiquidPiston INC. for providing all the laboratorial conditions to perform the experiments, MEtRICs - Mechanical Engineering and Resource Sustainability Centre (UID/EMS/04077/2019), and Diogo Ferreira for aiding in the highspeed visualization setup and experiments. T. Costa is supported by the Portuguese Foundation for Science and Technology (FCT) under the PhD grant PD/BD/105929/2014, MIT Portugal Program, and F.P. Brito is supported by FCT under the Post doctoral grant SFRH/BPD/89553/2012 and J. Martins is supported by the FCT grant SFRH/BSAB/142994/2018, financed by FEDER funds through Programa Operacional Fatores de Competitividade - COMPETE and National funds through PIDDAC and FCT.Pergamon-Elsevier Science LtdUniversidade do MinhoCosta, TiagoMartins, JorgeBrito, F.P.Oliveira Panao, Miguel R.Moreira, Antoio L. N.20192019-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/1822/66264engT. Costa, J. Martins, F.P. Brito, M.R. Oliveira Panão, A.L.N. Moreira, The Effect ofAmbient Pressure on the Heat Transfer of a Water Spray, Applied Thermal Engineering (2019), doi: https://doi.org/10.1016/j.applthermaleng.2019.02.0891359-431110.1016/j.applthermaleng.2019.02.089info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-07-21T12:24:21ZPortal AgregadorONG |
dc.title.none.fl_str_mv |
The effect of ambient pressure on the heat transfer of a water spray |
title |
The effect of ambient pressure on the heat transfer of a water spray |
spellingShingle |
The effect of ambient pressure on the heat transfer of a water spray Costa, Tiago Spray cooling Transient wall heat flux High Ambient Pressure Science & Technology |
title_short |
The effect of ambient pressure on the heat transfer of a water spray |
title_full |
The effect of ambient pressure on the heat transfer of a water spray |
title_fullStr |
The effect of ambient pressure on the heat transfer of a water spray |
title_full_unstemmed |
The effect of ambient pressure on the heat transfer of a water spray |
title_sort |
The effect of ambient pressure on the heat transfer of a water spray |
author |
Costa, Tiago |
author_facet |
Costa, Tiago Martins, Jorge Brito, F.P. Oliveira Panao, Miguel R. Moreira, Antoio L. N. |
author_role |
author |
author2 |
Martins, Jorge Brito, F.P. Oliveira Panao, Miguel R. Moreira, Antoio L. N. |
author2_role |
author author author author |
dc.contributor.none.fl_str_mv |
Universidade do Minho |
dc.contributor.author.fl_str_mv |
Costa, Tiago Martins, Jorge Brito, F.P. Oliveira Panao, Miguel R. Moreira, Antoio L. N. |
dc.subject.por.fl_str_mv |
Spray cooling Transient wall heat flux High Ambient Pressure Science & Technology |
topic |
Spray cooling Transient wall heat flux High Ambient Pressure Science & Technology |
description |
The present work is aimed at quantifying the effects of ambient pressure in the heat transfer at single injections of a full cone spray over a hot metal surface. The experimental configuration is that of a spray impinging down perpendicularly onto a flat surface located at 55 mm inside an injection chamber. The experiments were conducted for prescribed initial wall temperatures ranging from single phase to local nucleate boiling and transition regimes of heat transfer. Ambient pressures ranged from atmospheric to 30 bar. The analysis is based on spatial resolved measurements of the instantaneous surface temperature during the injection period. The measurements are then processed in order to obtain estimates of the time-averaged values of the local heat flux. The overall cooling rate is also obtained by integrating the local values within the total area of the spray impact Results show that the amount of heat extracted by the impinging spray increases 3.4 times when ambient pressure is increased from atmospheric to 20 bar at the same superheating degree at the wall of 45 degrees C. This corresponds to an increase from 13.3% to 47.7% in the ratio between the actual cooling and the theoretical maximum cooling, defined here as cooling efficiency. This is a result of a better spreading of the liquid film at the wall, covering a larger footprint upon impact. Instantaneous peak heat flux is also increased, as a clear indication of the improved heat transfer between the impinging droplets and the wall.The work presented herein derives from a broader research program devised to develop a system for in cylinder cooling of internal combustion engines using high pressure water sprays produced by gasoline direct injectors. |
publishDate |
2019 |
dc.date.none.fl_str_mv |
2019 2019-01-01T00:00:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/1822/66264 |
url |
http://hdl.handle.net/1822/66264 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
T. Costa, J. Martins, F.P. Brito, M.R. Oliveira Panão, A.L.N. Moreira, The Effect ofAmbient Pressure on the Heat Transfer of a Water Spray, Applied Thermal Engineering (2019), doi: https://doi.org/10.1016/j.applthermaleng.2019.02.089 1359-4311 10.1016/j.applthermaleng.2019.02.089 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Pergamon-Elsevier Science Ltd |
publisher.none.fl_str_mv |
Pergamon-Elsevier Science Ltd |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
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repository.mail.fl_str_mv |
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1777303749604147200 |