The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities in large space: fractal dimension of cellular-flame fronts
The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities were numerically investigated. Two-dimensional reactive flow was calculated in large space, based on the compressible Navier-Stokes equations inclu...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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The Japan Society of Mechanical Engineers
2017-06-01
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| Series: | Journal of Thermal Science and Technology |
| Subjects: | |
| Online Access: | https://www.jstage.jst.go.jp/article/jtst/12/1/12_2017jtst0015/_pdf/-char/en |
| _version_ | 1831812443948449792 |
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| author | Satoshi KADOWAKI Taisuke WASHIO Thwe Thwe Aung Wataru YAMAZAKI Toshiyuki KATSUMI Hideaki KOBAYASHI |
| author_facet | Satoshi KADOWAKI Taisuke WASHIO Thwe Thwe Aung Wataru YAMAZAKI Toshiyuki KATSUMI Hideaki KOBAYASHI |
| author_sort | Satoshi KADOWAKI |
| collection | DOAJ |
| description | The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities were numerically investigated. Two-dimensional reactive flow was calculated in large space, based on the compressible Navier-Stokes equations including a one-step irreversible chemical reaction. The dynamic behavior of cellular premixed flames, i.e. the coalescence and division of cells, appeared in large space owing to intrinsic instability. The behavior of flame fronts became more unstable with a decrease in unburned-gas temperature, even though the burning velocity of a planar flame reduced. This was due to the strength of thermal-expansion effects and to the enlargement of Zeldovich numbers. We found that the average burning velocity of a cellular flame normalized by that of a planar flame increased as the unburned-gas temperature became lower and the space size became larger. To elucidate the increase of burning velocity, we proposed the new model and showed that the normalized increment factor of burning velocity became larger under low unburned-gas temperature. In addition, we performed fractal analysis to consider the fractal dimension for three-dimensional flow. The obtained fractal dimension corresponding to laminar flames was nearly identical to the experimental and numerical results of turbulent flames. |
| first_indexed | 2024-12-22T21:36:32Z |
| format | Article |
| id | doaj.art-19a7a0659bcd4472806fd55054fabf0b |
| institution | Directory Open Access Journal |
| issn | 1880-5566 |
| language | English |
| last_indexed | 2024-12-22T21:36:32Z |
| publishDate | 2017-06-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Journal of Thermal Science and Technology |
| spelling | doaj.art-19a7a0659bcd4472806fd55054fabf0b2022-12-21T18:11:43ZengThe Japan Society of Mechanical EngineersJournal of Thermal Science and Technology1880-55662017-06-01121JTST0015JTST001510.1299/jtst.2017jtst0015jtstThe effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities in large space: fractal dimension of cellular-flame frontsSatoshi KADOWAKI0Taisuke WASHIO1Thwe Thwe Aung2Wataru YAMAZAKI3Toshiyuki KATSUMI4Hideaki KOBAYASHI5Department of System Safety, Nagaoka University of TechnologyDepartment of Mechanical Engineering, Nagaoka University of TechnologyDepartment of Mechanical Engineering, Nagaoka University of TechnologyDepartment of Mechanical Engineering, Nagaoka University of TechnologyDepartment of Mechanical Engineering, Nagaoka University of TechnologyInstitute of Fluid Science, Tohoku UniversityThe effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities were numerically investigated. Two-dimensional reactive flow was calculated in large space, based on the compressible Navier-Stokes equations including a one-step irreversible chemical reaction. The dynamic behavior of cellular premixed flames, i.e. the coalescence and division of cells, appeared in large space owing to intrinsic instability. The behavior of flame fronts became more unstable with a decrease in unburned-gas temperature, even though the burning velocity of a planar flame reduced. This was due to the strength of thermal-expansion effects and to the enlargement of Zeldovich numbers. We found that the average burning velocity of a cellular flame normalized by that of a planar flame increased as the unburned-gas temperature became lower and the space size became larger. To elucidate the increase of burning velocity, we proposed the new model and showed that the normalized increment factor of burning velocity became larger under low unburned-gas temperature. In addition, we performed fractal analysis to consider the fractal dimension for three-dimensional flow. The obtained fractal dimension corresponding to laminar flames was nearly identical to the experimental and numerical results of turbulent flames.https://www.jstage.jst.go.jp/article/jtst/12/1/12_2017jtst0015/_pdf/-char/encellular premixed flamedynamic behaviorintrinsic instabilityunburned-gas temperaturefractal dimension |
| spellingShingle | Satoshi KADOWAKI Taisuke WASHIO Thwe Thwe Aung Wataru YAMAZAKI Toshiyuki KATSUMI Hideaki KOBAYASHI The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities in large space: fractal dimension of cellular-flame fronts Journal of Thermal Science and Technology cellular premixed flame dynamic behavior intrinsic instability unburned-gas temperature fractal dimension |
| title | The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities in large space: fractal dimension of cellular-flame fronts |
| title_full | The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities in large space: fractal dimension of cellular-flame fronts |
| title_fullStr | The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities in large space: fractal dimension of cellular-flame fronts |
| title_full_unstemmed | The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities in large space: fractal dimension of cellular-flame fronts |
| title_short | The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities in large space: fractal dimension of cellular-flame fronts |
| title_sort | effects of unburned gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive thermal instabilities in large space fractal dimension of cellular flame fronts |
| topic | cellular premixed flame dynamic behavior intrinsic instability unburned-gas temperature fractal dimension |
| url | https://www.jstage.jst.go.jp/article/jtst/12/1/12_2017jtst0015/_pdf/-char/en |
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