| Project/Area Number |
09650255
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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 | TOKYO DENKI UNIVERSITY |
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Principal Investigator |
YOSHIDA Akira Tokyo Denki University, Department of Mechnical Engineering, Professor, 工学部, 教授 (40105680)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Hydrogen / Counterflow Flame / Extinction / Premixed Flame / Lewis Number / Stagnation Flow / Turbulent Flame / Flame Stretch / 対向流火災 / 予混合火災 / 乱流火災 / 火災伸長 / 水素燃焼 / ルイス教 / レーザー流速計 / 対向流バ-ナ / 多孔質円筒 |
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| Research Abstract |
Hydrogen is the promising fuel for future. The characteristic feature of he hydrogen-air premixed flame was investigated using the counterflow burner. The hydrogen-air mixtures within the inflammability limits were ejected from the porous cylinder. The hydrogen-air mixture of same equivalence ratio and uniform velocity distribution from the conversing nozzle was supplied from the bottom. The stable double flame was produced in the stagnation region of the impinging flowfield. In the present study, the flame produced in the counterflow were investigated the extinction mechanism of laminar hydrogen-air flame by varuing the equivalence ratio and the effect of the turbulence on the extinction phenomenon.
It was made clear that the large amount of the hydrogen is needed to extinguish the hydrogen-air flame by flame stretch only. Therefore the hydrogen fuel is diluted by the nitrogen and we constructed the nitrogen supply system to extinguish the hydrogen-air flame at small amount of the hydr
… More
ogen. Firstly, the fuel was diluted by 85% with nitrogen. As a result, on the lean side the extinction limit at which the flame was extinguished increases with the equivalence ratio and the maximum appeared at the equivalence ratio of 1.0. The distance of the upper and lower flame decreased and extinction limit appears due to the incomplete combustion and heat loss. On the other hand, for the rich flames the extinction limit decreases again. The distance between two flames is far even at the state of extinction and extinction occurs only due to flame stretch. Therefore the Lewis number is the important parameter for flame extinction.
We were intended to involve the effect of turbulence on flame extinction. However, it was very time consuming to construct the hydrogen and nitrogen supply system and flow controlling system. So the effect of turbulence on the flame extinction could not measure in the present study. However, we have establised the procedure of experiments of dangerous hydrogen-air mixture. Less
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