Unstable behavior of hydrogen-air lean premixed flames (Effects of unburned-gas temperature, heat loss and scale)
Unstable behavior of hydrogen-air lean premixed flames was studied by numerical calculations of two-dimensional unsteady reactive flow to clarify the effects of unburned-gas temperature, heat loss and scale. We adopted the numerical model containing the detailed hydrogen-oxygen combustion with 17 e...
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Format: | Article |
Language: | Japanese |
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The Japan Society of Mechanical Engineers
2020-03-01
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Series: | Nihon Kikai Gakkai ronbunshu |
Subjects: | |
Online Access: | https://www.jstage.jst.go.jp/article/transjsme/86/883/86_19-00401/_pdf/-char/en |
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author | Satoshi KADOWAKI Tsutomu UCHIYAMA Toshiyuki KATSUMI Thwe Thwe Aung Hideaki KOBAYASHI |
author_facet | Satoshi KADOWAKI Tsutomu UCHIYAMA Toshiyuki KATSUMI Thwe Thwe Aung Hideaki KOBAYASHI |
author_sort | Satoshi KADOWAKI |
collection | DOAJ |
description | Unstable behavior of hydrogen-air lean premixed flames was studied by numerical calculations of two-dimensional unsteady reactive flow to clarify the effects of unburned-gas temperature, heat loss and scale. We adopted the numerical model containing the detailed hydrogen-oxygen combustion with 17 elementary reactions of 8 reactive species and a nitrogen diluent, compressibility, viscosity, heat conduction, molecular diffusion, and heat loss of Newtonian type. A disturbance with sufficiently small amplitude was superimposed on a planar flame to obtain the relation between the growth rate and wave number, i.e. dispersion relation, and the linearly most unstable wave number, i.e. critical wave number. As the unburned-gas temperature became lower and the heat loss increased, the growth rate decreased and the unstable range narrowed. These were due mainly to the decrease of flame temperature and burning velocity. To study the characteristics of cellular flames, the disturbance with the critical wave number was superimposed. The disturbance developed owing to intrinsic instability, and then the cellular shape of flame fronts appeared. The burning velocity of a cellular flame normalized by that of a planar flame became larger as the unburned-gas temperature became lower and the heat loss increased. The burning velocity of a cellular flame became monotonically larger with an increase in scale. This was because that the long-wavelength components of disturbances affected the unstable behavior of cellular flames. |
first_indexed | 2024-04-11T15:28:36Z |
format | Article |
id | doaj.art-08f3ad7284894afd994fb3b958cd63fe |
institution | Directory Open Access Journal |
issn | 2187-9761 |
language | Japanese |
last_indexed | 2024-04-11T15:28:36Z |
publishDate | 2020-03-01 |
publisher | The Japan Society of Mechanical Engineers |
record_format | Article |
series | Nihon Kikai Gakkai ronbunshu |
spelling | doaj.art-08f3ad7284894afd994fb3b958cd63fe2022-12-22T04:16:11ZjpnThe Japan Society of Mechanical EngineersNihon Kikai Gakkai ronbunshu2187-97612020-03-018688319-0040119-0040110.1299/transjsme.19-00401transjsmeUnstable behavior of hydrogen-air lean premixed flames (Effects of unburned-gas temperature, heat loss and scale)Satoshi KADOWAKI0Tsutomu UCHIYAMA1Toshiyuki KATSUMI2Thwe Thwe Aung3Hideaki KOBAYASHI4Department of System Safety, Nagaoka University of TechnologyDepartment of Mechanical Engineering, Nagaoka University of TechnologyDepartment of Mechanical Engineering, Nagaoka University of TechnologyCollaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy AgencyInstitute of Fluid Science, Tohoku UniversityUnstable behavior of hydrogen-air lean premixed flames was studied by numerical calculations of two-dimensional unsteady reactive flow to clarify the effects of unburned-gas temperature, heat loss and scale. We adopted the numerical model containing the detailed hydrogen-oxygen combustion with 17 elementary reactions of 8 reactive species and a nitrogen diluent, compressibility, viscosity, heat conduction, molecular diffusion, and heat loss of Newtonian type. A disturbance with sufficiently small amplitude was superimposed on a planar flame to obtain the relation between the growth rate and wave number, i.e. dispersion relation, and the linearly most unstable wave number, i.e. critical wave number. As the unburned-gas temperature became lower and the heat loss increased, the growth rate decreased and the unstable range narrowed. These were due mainly to the decrease of flame temperature and burning velocity. To study the characteristics of cellular flames, the disturbance with the critical wave number was superimposed. The disturbance developed owing to intrinsic instability, and then the cellular shape of flame fronts appeared. The burning velocity of a cellular flame normalized by that of a planar flame became larger as the unburned-gas temperature became lower and the heat loss increased. The burning velocity of a cellular flame became monotonically larger with an increase in scale. This was because that the long-wavelength components of disturbances affected the unstable behavior of cellular flames.https://www.jstage.jst.go.jp/article/transjsme/86/883/86_19-00401/_pdf/-char/enpremixed combustionhydrogen flameunstable behaviorunburned-gas temperatureheat lossscaleburning velocity |
spellingShingle | Satoshi KADOWAKI Tsutomu UCHIYAMA Toshiyuki KATSUMI Thwe Thwe Aung Hideaki KOBAYASHI Unstable behavior of hydrogen-air lean premixed flames (Effects of unburned-gas temperature, heat loss and scale) Nihon Kikai Gakkai ronbunshu premixed combustion hydrogen flame unstable behavior unburned-gas temperature heat loss scale burning velocity |
title | Unstable behavior of hydrogen-air lean premixed flames (Effects of unburned-gas temperature, heat loss and scale) |
title_full | Unstable behavior of hydrogen-air lean premixed flames (Effects of unburned-gas temperature, heat loss and scale) |
title_fullStr | Unstable behavior of hydrogen-air lean premixed flames (Effects of unburned-gas temperature, heat loss and scale) |
title_full_unstemmed | Unstable behavior of hydrogen-air lean premixed flames (Effects of unburned-gas temperature, heat loss and scale) |
title_short | Unstable behavior of hydrogen-air lean premixed flames (Effects of unburned-gas temperature, heat loss and scale) |
title_sort | unstable behavior of hydrogen air lean premixed flames effects of unburned gas temperature heat loss and scale |
topic | premixed combustion hydrogen flame unstable behavior unburned-gas temperature heat loss scale burning velocity |
url | https://www.jstage.jst.go.jp/article/transjsme/86/883/86_19-00401/_pdf/-char/en |
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