2007 Fiscal Year Final Research Report Summary
Investigation of Turbulent Flame Propagation Mechanism and Development of Turbulent Combustion Model
| Project/Area Number |
18560204
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | Kyushu University |
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Principal Investigator |
KITAGAWA Toshiaki Kyushu University, Faculty of Engineering, Professor (40214788)
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| Co-Investigator(Kenkyū-buntansha) |
MORIYOSHI Yasuo Chiba University, Faculty of Engineering, Associate Professor (40230172)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Turbulent Flame / Burning Velocity / Combustion Model / Flame Stretch / Pressure / Markstein Number / Lewis Number / Lewis Number |
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| Research Abstract |
In order to develop universal turbulent combustion model applicable at elevated pressures for a lot of fuels having various combustion properties such as laminar burning velocity, laminar and turbulent combustion was studied for gaseous fuels of hydrogen, methane, propane, and liquid fuel of iso-octane. Laminar burning velocities, Markstein numbers and turbulent burning velocities were obtained for lean to rich mixtures of these fuels at 0.10 to 0.50MPa.
The ratio of turbulent burning velocity to unstretched laminar burning velocity was found to depend on the turbulence Reynolds number, the ratio of turbulence intensity to unstretched laminar burning velocity, and the Markstein number. Among these three dominant factors, the turbulence Reynolds number and the Markstein number were reduced to one factor of the combination of the turbulence Reynolds and Lewis numbers, the turbulence Reynolds number divided by the square of the Lewis number. After all, turbulent burning velocities at various pressures were found to correlate with two parameters of the ratio of turbulence intensity to unstretched laminar burning velocity, and the turbulence Reynolds number divided by the square of the Lewis number. In addition to the above results, turbulent burning velocity at a constant Peclet number was found to correlate with the Karlovitz number. In all results in this study, thermo-diffusive effects were found to affect turbulent flames.
Finally, variations of turbulent burning velocity during explosions were formulated in terms of flame radius. The coefficient in the formulation was found to depend on the turbulence Reynolds number, the ratio of turbulence intensity to unstretched laminar burning velocity, and the Markstein number.
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