2006 Fiscal Year Final Research Report Summary
The Dynamism of Combustion and Flame of Three-Dimensionally Dispersed Fuel System under Microgravity Conditions
| Project/Area Number |
16360108
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Osaka Prefecture University |
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Principal Investigator |
KADOTA Toshikazu Osaka Prefecture University, Graduate School of Engineering, Professor, 工学研究科, 教授 (70034402)
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| Co-Investigator(Kenkyū-buntansha) |
SEGAWA Daisuke Osaka Prefecture University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (00264804)
NAKAYA Shinji Osaka Prefecture University, Graduate School of Engineering, Instructor, 工学研究科, 助手 (00382234)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Liquid fuel / Combustion / Droplet cluster / Droplet array / Flame structure / Microgravity environment / Non-intrusive measurement / Autoignition |
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| Research Abstract |
The objective of the present research was to observe the successive unsteady processes from evaporation to combustion after autoignition of fuel droplet clusters, which were the three-dimensionally dispersed fuel systems, and to elucidate the effects of primary factors on the processes. Experiments were mainly conducted in the present study, and microgravity environments were utilized in the experiments for reducing the effects of natural convection, which complicated the phenomena of attention. Droplet arrays and single droplets were also included as the experimental objects. Non-intrusive measurement with LIF method and numerical simulation of radical species in the flames were conducted for deeper understanding.
The experimental objects were the droplet clusters with about 50 droplets, those with about 10 droplets, the droplet arrays with about 10 droplets and the single droplets. For the single droplets, we focused our attention on the effects of properties of the fuel and the ambient gas, and elucidated the conventional combustion characteristics in the microgravity experiments. We also conducted the droplet experiments in weak flows under the normal gravity condition, where the effects of natural convection were relatively reduced, and elucidated the distributions of soot and hydroxyl radical inside the droplet flame. The mode map of the flame shape and extinction was made with the gas velocity and the droplet diameter as the variables. The results on the radical distribution were reproduced in the simulation, which included a detailed reaction model, and the obtained effects of the ambient gas humidity were confirmed. Also elucidated were the effects of the droplet spacing, the fuel properties and the ambient gas velocity on the flame spread speed of the droplet array, and the droplet spacing effects on the unsteady evaporation process, on the delay time of autoignition and on the behavior of the flame growth of the droplet clusters in microgravity.
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Research Products
(3 results)
