1991 Fiscal Year Final Research Report Summary
Burning Characteristics of Tubular Flame at High Pressure
| Project/Area Number |
62460071
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Aerospace engineering
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| Research Institution | Nagoya University (1988-1989)
The University of Tokyo (1987) |
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Principal Investigator |
TAKENO Tadao Nagoya University, Mechanical Engineering, Professor, 工学部, 教授 (90013672)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIOKA Makihito Nagoya University, Mechanical Engineering, Research Associate, 工学部, 助手 (70208148)
ISIZUKA Satoru Tokyo University, Reaction Chemistry, Associate Professor, 工学部, 助教授 (70129162)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Tubular Flame / High Pressure Combustion / Element of Turbulent Flame |
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| Research Abstract |
The effects of pressure on stability and diameter(radius)of lean methane-air tubular flame were investigated by means of both experiment and numerical calculation with full kinetic mechanism. The pressure was varied from 1 to 4 atm. The conclusions are as follows.
1. At a given pressure, flame can only be stabilized within a region determined by fuel concentration and ejection velocity of premixed gas.
2. At a fixed pressure, when ejection velocity is increased the lean limit of fuel concentration is increased and the stable region becomes narrower.
3. When pressure is increased, the lean limit of fuel concentration increases and the stable region becomes narrower.
4. At fixed pressure and ejection velocity, flame diameter increases with fuel concentration. And at fixed pressure and fuel concentration, flame diameter decreases with ejection velocity.
5. At fixed ejection velocity and fuel concentration, flame diameter decreases with pressure.
Furthermore, the effects of radial velocity gradient on behaviors of stoichiometric methane-air tubular flame at pressure from 1 to 8 atm were investigated by means of numerical calculation mentioned above. The conclusions are as follows.
6. At any pressure, when velocity gradient increases, flame radius and flame temperature decrease. And at a critical velocity gradient the flame finally extinguishes.
7. At a fixed velocity gradient, when pressure increases, flame radius decreases and flame temperature increases.
8. The critical velocity gradient at which extinction occurs increases with pressure below 2.7 atm, and decreases above that.
9. The flame radius at extinction, which corresponds to the minimum radius, decreases with pressure and approaches to around 0.2mm. Thus, at higher pressure flame with smaller radius is not thought to be realized.
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