| Project/Area Number |
01550180
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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 | Kyushu University |
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Principal Investigator |
ONO Shinsuke Kyushu University Faculty of Engineering, Professor, 工学部, 教授 (80037738)
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| Co-Investigator(Kenkyū-buntansha) |
KAWANO Hideaki Kyushu University Faculty of Engineering, Research Associate, 工学部, 助手 (30037915)
HANADA Kunihiko Kyushu University Faculty of Engineering, Research Associate, 工学部, 助手 (30037874)
MURASE Eiichi Kyushu University Faculty of Engineering, Associate Professor, 工学部, 助教授 (60150504)
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| Project Period (FY) |
1989 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1989: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Centrifugal Acceleration / Swirl / Flame Extinction / Flame Propagation / Flamabilty Limit / Lewis Number / Convective Motion / Laminarization / 遠心力 / 対流 / 火災伝播 / 希薄混合気 |
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| Research Abstract |
Flame propagation in a swirl flow shows complicated behaviors due to the intense turbulence accompanied by the swirl. In this study, by making use of the rotary combustion device which rotates with mixture in it, the real effects of the rotating flow environments on the flame behaviors are investigated. The experimental results make clear that the enhanced combustion by the swirl cannot always be realized because of the rapid motion of a flame kernel toward the center and the laminarization of turbulent flame front in the intense rotating flow. The experimental results are summarized as follows :
(1)A rapid expansion of the burned gas ignited at the vessel center may suppress the growth of flame due to disturbance caused by a mechanical non-equilibrium existing between unburned and burned gas, and may cause a flame extinction, depending on the condition.
(2)In the case of the ignition near the vessel wall, flame quickly moves to the vessel center and the flame zone develops more than for the central ignition. But, the laminatization of the turbulent flame zone soon appears to follow the similar process to the central ignition. Although the extinction radius becomes larger than that for the central ignition, the extinction time(burnig period)still remains approximately the same as that for the central ignition.
(3)The extinction limit seems to be determined by the relative relation between a flame propagation speed and a flame convection speed. The extinction tendency becomes considerable with the increase of the ratio, Vc/Vf.
(4)With the exception of the influence of the rotation speed, the degree of influence considerably depends on the preheat zone thickness, the burning velocity, and the lewis number that are related to the flame structure.
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