| Project/Area Number |
05650197
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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 | The University of Tokushima |
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Principal Investigator |
MIWA Kei The University of Tokushima, Faculty of Engineering Professor, 工学部, 教授 (00026147)
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| Co-Investigator(Kenkyū-buntansha) |
MIYASHIRO Seiji Anan College of Technologh, 教授 (90018010)
ISHIYAMA Takuji The University of Tokushima, Faculty of Engineering Lecturer, 工学部, 講師 (30203037)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1993: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Combustion / Spray / Atomization / Ignition / Image analysis / Mixture formation / 内燃機関 / ディーゼル機関 / パルス光源 / 画像処理 |
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| Research Abstract |
The purpose of this study is to make clear physical process, fuel disintegration and atomization, that is included in initial mixture formation process by transient fuel sprays in high temperature and pressure air. Light diesel oil sprays injected into high pressure inert gas were studied by taking and analyzing photographs with high resolution of time and space. For this purpose, nano-spark light sources were constructed. Because the light sources emit light pulses with the duration of less than 30 nanoseconds, each droplet moving at high speed can be frozen as an image on a film and can be measured in terms of the size and shape using a high magnification lens system and the image analysis algorithm developed in this study. Using this photographic system, initial sparays up to 500mus from the start of injection were studied. The main results are as follows.
(1) The shape of fuel flow is very complicated caused by the flow pattern inside the injector just after the start of injection.
(2) There are many long ligaments as strings around the tip of a spray injected into low pressure embironment. On the other hand, under the high pressure, smaller and spherical droplets are found in the downstream of branch like structure.
(3) At about 200mus after the start of injection, the scale of disintegration suddenly increases and many branch like structures become the source of disintegration in place of the spray tip.
(4) Many small droplets are found in the vicinity of the nozzle tip even before 100mus. It is suggested that this droplet cloud will produce initial mixture which is oxidized to give heat to fuel and causes its gasfication. Ignition process of the spray will begin with the formation of this droplet cloud.
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