| Project/Area Number |
10450075
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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 |
Fluid engineering
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| Research Institution | Nagaoka University of Technology |
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Principal Investigator |
MASUDA Wataru Faculty of Engineering, Nagaoka University of Technology Professor, 工学部, 教授 (80143816)
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| Co-Investigator(Kenkyū-buntansha) |
HISHIDA Manabu Nagoya University Lecturere Graduate School Faculty of Engineering, 大学院・工学研究科, 講師 (60262870)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 1999: ¥5,200,000 (Direct Cost: ¥5,200,000)
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| Keywords | Supersonic Flow / Laser / Iodine / Chemical Laser / 超音速混合 / ランプノズル / 混合促進 / ナビエ・ストークス / 詳細反応モデル / 縦渦 / 音響励振 / 分岐 |
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| Research Abstract |
Possibility of mixing enhancement of iodine with singlet oxygen by means of acoustic excitationwas examined using a jet-diffusion flame of methane. The jet-diffusion flame was acoustically excited by monotone sound wave generated by a loud speaker. Applying the acoustic excitation using a specific range of frequency that corresponds to the Strouhal number St=0.15 to 0.6, the jet diffusion flame has peculiar features. In the mode of increasing the jet velocity, the flame shortens its original length and widened in the incident direction of sound wave. Decreasing the jet velocity, the jet velocity at which the reattachment of lifted flame occurs is lowered significantly owing to the acoustic excitation, and the lifted flames with elliptical cross sections or branched tips are discovered in the specific region of the velocity and sound frequency.
A Q-switched supersonic flow chemical oxygen-iodine laser is also simulated by solving the gas flow model coupled with the precis e chemical kinetic model and the optical model. The model includes the effects of hyperfine relaxation and velocity cross relaxation for iodine atoms. The effects of such relaxations and nonuniformity of the three-dimensional flow field on the power extraction were discussed. The results show that the peak power under the influence of hyperfine relaxation and velocity cross relaxation, which is normalized to the corresponding continuous wave value, is 15. It agrees fairly well with common experimental results of Q-switched chemical oxygen-iodine laser operation. The peak power of the pulse in the three-dimensional flow field is considerably small compared to that in the equivalent one-dimensional flow field and the pulse is widened roughly twice due to insufficient mixing, shock waves, expansion waves and wakes.
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