Comparison of Presumed PDF Models of Turbulent Flames
Over the past years, the use of a presumed probability density function (PDF) for combustion progress variable or/and mixture fraction has been becoming more and more popular approach to average reaction rates in premixed and partially premixed turbulent flames. Commonly invoked for this purpose is...
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| Format: | Article |
| Language: | English |
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Wiley
2012-01-01
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| Series: | Journal of Combustion |
| Online Access: | http://dx.doi.org/10.1155/2012/564621 |
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| author | Chen Huang Andrei N. Lipatnikov |
| author_facet | Chen Huang Andrei N. Lipatnikov |
| author_sort | Chen Huang |
| collection | DOAJ |
| description | Over the past years, the use of a presumed probability density function (PDF) for combustion progress variable or/and mixture fraction has been becoming more and more popular approach to average reaction rates in premixed and partially premixed turbulent flames. Commonly invoked for this purpose is a beta-function PDF or a combination of Dirac delta functions, with the parameters of the two PDFs being determined based on the values of their first and second moments computed by integrating proper balance equations. Because the choice of any of the above PDFs appears to be totally arbitrary as far as underlying physics of turbulent combustion is concerned, the use of such PDFs implies weak sensitivity of the key averaged quantities to the PDF shape. The present work is aimed at testing this implicit assumption by comparing mean heat release rates, burning velocities, and so forth, averaged by invoking the aforementioned PDFs, with all other things being equal. Results calculated in the premixed case show substantial sensitivity of the mean heat release rate to the shape of presumed combustion-progress-variable PDF, thus, putting the approach into question. To the contrary, the use of a presumed mixture-fraction PDF appears to be a sufficiently reasonable simplification for modeling the influence of fluctuations in the mixture fraction on the mean burning velocity provided that the mixture composition varies within flammability limits. |
| format | Article |
| id | doaj-art-f74f0bc4b0cd4c288cccb0a463da842b |
| institution | Kabale University |
| issn | 2090-1968 2090-1976 |
| language | English |
| publishDate | 2012-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Journal of Combustion |
| spelling | doaj-art-f74f0bc4b0cd4c288cccb0a463da842b2025-02-03T05:49:45ZengWileyJournal of Combustion2090-19682090-19762012-01-01201210.1155/2012/564621564621Comparison of Presumed PDF Models of Turbulent FlamesChen Huang0Andrei N. Lipatnikov1Department of Applied Mechanics, Chalmers University of Technology, 412 96 Gothenburg, SwedenDepartment of Applied Mechanics, Chalmers University of Technology, 412 96 Gothenburg, SwedenOver the past years, the use of a presumed probability density function (PDF) for combustion progress variable or/and mixture fraction has been becoming more and more popular approach to average reaction rates in premixed and partially premixed turbulent flames. Commonly invoked for this purpose is a beta-function PDF or a combination of Dirac delta functions, with the parameters of the two PDFs being determined based on the values of their first and second moments computed by integrating proper balance equations. Because the choice of any of the above PDFs appears to be totally arbitrary as far as underlying physics of turbulent combustion is concerned, the use of such PDFs implies weak sensitivity of the key averaged quantities to the PDF shape. The present work is aimed at testing this implicit assumption by comparing mean heat release rates, burning velocities, and so forth, averaged by invoking the aforementioned PDFs, with all other things being equal. Results calculated in the premixed case show substantial sensitivity of the mean heat release rate to the shape of presumed combustion-progress-variable PDF, thus, putting the approach into question. To the contrary, the use of a presumed mixture-fraction PDF appears to be a sufficiently reasonable simplification for modeling the influence of fluctuations in the mixture fraction on the mean burning velocity provided that the mixture composition varies within flammability limits.http://dx.doi.org/10.1155/2012/564621 |
| spellingShingle | Chen Huang Andrei N. Lipatnikov Comparison of Presumed PDF Models of Turbulent Flames Journal of Combustion |
| title | Comparison of Presumed PDF Models of Turbulent Flames |
| title_full | Comparison of Presumed PDF Models of Turbulent Flames |
| title_fullStr | Comparison of Presumed PDF Models of Turbulent Flames |
| title_full_unstemmed | Comparison of Presumed PDF Models of Turbulent Flames |
| title_short | Comparison of Presumed PDF Models of Turbulent Flames |
| title_sort | comparison of presumed pdf models of turbulent flames |
| url | http://dx.doi.org/10.1155/2012/564621 |
| work_keys_str_mv | AT chenhuang comparisonofpresumedpdfmodelsofturbulentflames AT andreinlipatnikov comparisonofpresumedpdfmodelsofturbulentflames |