| Project/Area Number |
06650239
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | Gifu University |
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Principal Investigator |
KATSUO Asato Gifu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (00021626)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1994: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Premixed combustion / Vortex / Flame propagation / Flame speed / Flame stretch / Lewis number / Extinction limit |
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| Research Abstract |
The effects of the Lewis number Le on the limits of flame propagation and the flame speed, and the effects of the stretched vortex core on flame speed in a single well-characterized vortex core were examined experimentally using a vortex ring generated by a pulse jet of the mixture ejected through a circular nozzle. The limit of flame propagation in the vortex core for the mixtures of Le <1.0 is more extended than that for the mixtures of Le>1.0. The flame speeds in the vortex core for the mixtures of Le<1.0 are higher than those for the mixtures of Le> 1.0. The flame speed has two values for a given value of the ratio of densities of the unburned gas to the burned gas (rho _u/ rho _b)^<1/2>, depending on the Lewis number of the limiting reactant.
The experiment of results on flame speed in the vortex core are not in quantitative agreement with the theoretical one calculated from Chomiak's model. The flame speed in the vortex core can be well predicted using the model of flame propagation in which the shape of the flame tip in the vortex core is considered. However, it is necessary to consider not only the shape of the flame tip in the vortex core but also the flame structure and the characteristics of chemical kinetic in order to predict the flame speed exactly.
The flame speed in the stretched vortex core is higher than that in the non-stretched vortex core because the maximum tangential velocity in the stretched vortex core is higher than that in the non-stretched vortex core.
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