| Project/Area Number |
60550141
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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 | TOHOKU UNIVERSITY |
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Principal Investigator |
NAGAI Nobuki Faculty of Engineering, Tohoku University, 工学部, 教授 (90005231)
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| Co-Investigator(Kenkyū-buntansha) |
INAMURA Takao Faculty of Engineering, Tohoku University, 工学部, 助手 (10143017)
HIRAI Tetsuro Faculty of Engineering, Tohoku University, 工学部, 助手 (60108462)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1985: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Liquid Atomization / Twin-Fluid Atomizer / Droplet Breakup / Flash Boiling Atomization / Spray Combustion / Single Drop Combustion / High Intensity Combustion / 粒子計測 |
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| Research Abstract |
In order to survey a efficient atomization method for coal-water slurry fuel (CWM), preparatory experiments of atomization have been carried out. In airblast atomization the prefilming atomizer showed better atomizing characteristics than the plain jet atomizer. Flash boiling atomization produced fine spray at high liquid temperature. Combustion experiments of single phase liquid fuel showed that high efficiency and low NOx emission can be realized under the condition of high intensity by the two staged combustion.
Practical experiments using commercial CWM have been conducted. The airblast atomization of a single CWM droplet resulted in that spray droplets are distinguished into irregular particles and spherical particles by the aerodynamic force. The model of disintegration mechanism was proposed based on binal agglomeration structure of CWM, and forecasted the change in atomizing characteristics against air velocity. A conventional plain jet atomizer proved the reasonability of that model, and the atomizing characteristics of this atomizer were clarified. From these results the twin-fluid atomizer was designed for a boiler and showed good combustion characteristics. On the other hand the experiments of flash boiling atomization changing coal concentration, degrees of superheat and injection pressure cleared the relation between atomizing characteristics and individual injection condition, and fine spray was produced at high liquid temperature over 150゜C. The influences of initial drop diameter and ambient gas temperature on the ignition delay and the burning time were investigated by the combustion of a single CWM drop. The burning time was also calculated by simple combustion model, and was compared with experimental results. We are now carrying out the experiments to investigate detailed combustion characteristics using the furnace designed so as to obtain the combustion of high intensity and low NOx emission.
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