1989 Fiscal Year Final Research Report Summary
A Study on Spray Combustion in Supercritical Environments
| Project/Area Number |
63460100
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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 |
Thermal engineering
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
HIROYASU Hiroyuki Hiroshima Univ., Faculty of Engineering, Professor, 工学部, 教授 (40034326)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIDA Keiya Hiroshima Univ., Faculty of Engineering, Associate Researcher, 工学部, 助手 (90156076)
ARAI Masataka Hiroshima Univ., Faculty of Engineering, Associate Professor, 工学部, 助教授 (80112176)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Spray / Supercritical Condition / Vapor Concentration / Mean Drop Diameter / Fraunhofer Diffraction / Holography / Schlieren / Image Processing |
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| Research Abstract |
A basic research was conducted on mechanisms of spray combustion in pressurized and heated ambient gas beyond the critical point of liquid fuel, that is, supercritical environments. The current research includes the following three items : (1) Blue Flame Combustion in a Jet-Mixing-Type Spray Combustor (2) Fuel Vapor Concentration and Mean Drop Diameter in a Spray Injected into Supercritical Environments (3) Drop Evaporation and Combustion in Supercritical Environments on a Hot Wall.
The principal results of the experiments listed above are as follows: (1) Mechanisms of blue flame combustion were investigated by the measurement of temperature distribution in a flame and the sampling analysis of combustion contents in a flame. Oxygen concentration and temperature around a nozzle in blue flame combustion were higher than in yellow flame combustion. Acetylene concentration in a flame showed higher value in a yellow flame. (2) Fuel vapor concentration in a spray injected into supercritical environments was measured by the image processing technique of a reconstructed hologram. The radial distribution of the fuel vapor concentration showed a low value at the center and the edge of the spray, and took a maximum between them. Mean drop diameter of the spray was measured by the optical analysis of the Fraunhofer diffraction light. The mean drop diameter increased once, then decreased with an increase of the ambient temperature. (3) Evaporation and combustion processes of a fuel drop in supercritical environments on a wall were observed in a pressure vessel. The evaporation lifetime in air was found to be shorter than that in nitrogen at the same wall temperature. As the ambient pressure increased beyond the critical pressure of the fuel, the end of combustion time increased in the wall temperature range just below the critical temperature of the fuel, and in the other temperature range it decreased.
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Research Products
(8 results)
