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論文
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小林, 佳弘 ; 斉藤, 孝充 ; 天谷, 賢児 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Since the engine combustion is affected by a variety of parameter such as well as fuel characteristics, it is very difficult to find out the clear effect of fuel property. In order to
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clarify the change of emission characteristic caused by fuel change, we propose a fundamental flame research method using a small pool-wick flame system. By using this system, PAHs (polycyclic aromatic hydrocarbons) formation mechanism in a flame was investigated as a fundamental study of diesel combustion. Characteristics of PAHs formation in a laminar diffusion flame were measured by a laser induced fluorescence (LIF) method. It was compared with PM charactersistics measured by a laser induced incandescence (LII) method. The effect of the lubricating oil contamination on the PAHs distributions in the flame was discussed. As the result, it was found that the PAHs concentration in the flame increased with increasing the lubricating oil contamination and it caused the increase of PM formation in the flame.
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| 2.
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川口, 知宏 ; 長瀧, 翼 ; 天谷, 賢児 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Ignition and combustion characteristics of diesel spray impinging on a wall were experimentally investigated. Ignition position and appearance position of the luminous flame
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kernel were stereoscopically observed using a two-way fiber optical system. Flat
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| 3.
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石井, 哲人 ; 佐藤, 博之 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />The effects of gravity on the fluctuation characteristics of turbulent diffusion flames were experimentally investigated. Super gravity fields were formed using a spin tester. The gravity
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level G was changed from 1 to 20, where G was defined as the value of super gravity per normal gravity. Flame states such as laminar, flickering and turbulent flames were observed under the various conditions of gravity level, G and Reynolds number, Re. The transition from laminar to turbulent and blow out limit were summarized on a G-Re map. Characteristics of turbulent fluctuation were measured by a laser light reflection method. Power spectra and auto-correlations were derived from the signal of laser intensity. As the result, it was found that the turbulent flame was begun to periodic oscillation with increasing the gravity level. Time scale of turbulent fluctuation in the super gravity became long than that in the normal gravity. Spectrum component in power spectrum shifted to the low frequency side when the gravity level became high. And the full width at half-maximum of autocorrelation peak became wider in the super gravity conditions.
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林田, 和宏 ; 天谷, 賢児 ; 佐藤, 桂司 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Raman scattering technique with KrF excimer laser was applied to obtain a fuel concentration distribution in a sooting flame. In the case of sooting flame, fluorescence from polycyclic
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aromatic hydrocarbons (PAH) and laser-induced incandescence (LII) from soot particles appeared with Raman scattering. These background emissions overlappped on the Raman scattering. In order to separate the Raman scattering and the background emissions, polarization property of laser-induced emissions was utilized. Since the background emissions were depolarized whereas the Raman scattering was highly polarized, it is possible to subtract the background emissions from the overlapping signal of the Raman scattering and the background emissions. Subtracting the emission signals for the electric vector of the laser light perpendicular and parallel to the direction of observation allows to extract the precise Raman signals. By using this technique, detailed fuel concentration distribution in sooting flames could be obtained based on Raman scattering.
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| 5.
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坂下, 直己 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Fuel droplet and vapor distributions in a spray flame formed in the hot air stream were measured by an exciplex fluorescence method. Kerosene was used as a test fuel. Kerosene was miscible
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with a small quantity of exciplex-forming dopants, TMPD (N, N, N', N'-tetramethyl-1,4-phenylene diamine) and naphthalene. A Nd : YAG laser (355nm) was used for excitation of the fuel. The fuel spray was injected from a swirl atomizer into an air stream. Air temperature was changed from room temperature to 1000k which was higher than the self-ignition temperature of a kerosene spray. Distributions of the fuel droplets and vapor were strongly affected by the air temperature. Furthermore it was confirmed that the fuel vapor was transported into recirculating flow area formed on the flame holder.
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| 6.
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斉藤, 正浩 ; 天谷, 賢児 ; 萩原, 五郎 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />To clarify the effect of water content on combustion characteristics of watery
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materials, combustion test of a high water-permeable balsa wood was performed using a thermogravimetric furnace. The furnace temperature is between 650℃ and 1000℃, and water contents in the small balsa pieces (0.3g) were varied up 70 wt%. Mass reduction during pre-heating, volatile matter combustion and char combustion were measured with a microbalance. Also, the variations of flame temperature and center temperature of the test piece during combustion process were measured. On the combustion of high water-contained balsa, it was found that ignition started before the water was evaporated completely. It means that two proceses, devolatilization of volatiles and vaporization of remaining water, are proceeding simultaneously during the volatile matter combustion. Ignition delay and retention time of volatile matter combustion increased with increasing the water content. The increases of flame temperature and center temperature of the test piece were prevented by the latent heat of water vaporization. The combustion rate of volatile matter was drastically reduced in proportion to the water content. Also, it was confirmed that a part of char burned during the latter stage of volatile matter combustion. The effect of water content on char combustion rate was small. From this study, it was concluded that the water content over 50 wt% affected remarkably to the volatile matter combustion.
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| 7.
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長谷川, 和之 ; 茂木, 俊夫 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Behavior of a spray combustion in a hot air was studied experimentally. A kerosene spray was injected from swirl atomizer into a hot air stream. The air temperature was controlled from room
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temperature to 1 100 K which was higher than the self-ignition temperature of a kerosene spray. Flame shape and temperature distribution were measured to characterize the spray combustion appeared in the hot air stream. Flow state around the spray was visualized by a Schlieren method to analyze the behavior of the air entrainment into the flame. Furthermore, Mie scattering from the spray droplets by irradiation of the laser beam was observed to visualize the spray concentration in a flame. As the result, ignition point was shifted to the upstream side with an increase of air temperature. When the air temperature became higher than 800 K, the blue flame appeared at the bottom portion of the flame. Penetration of the spray became shorter with an increase of air temperature. Spatial distribution of the spray which were not vaporized in a flame was strongly affected by the air temperature.
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