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| 1.
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小林, 佳弘 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Nano meter size particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) have harmful effects for human health. Investigations of the fundamental characteristic of PAHs behavior in
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combustion process were required for the establishment of the reduction technologies for nano-PM emission. In this paper, PAHs characteristics in diffusion flames of propane gas were investigated using laser diagnostic and gas sampling methods. A laser induced fluorescence (LIF) method was used to obtain the spatial distributions of PAHs. Spatial distributions of soot were also measured by a laser induced incandescence (LII) method. A transition region from PAHs to soot was defined from the results of LIF and LII. Further, PAH concentrations in the test flames were measured using a gas chromatography (GC), and the profiles of PAHs concentrations in the test flames were investigated. As the results, heavier molecules PAHs such as fluorene and pyrene were confirmed as precursors of soot.
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| 2.
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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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| 3.
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HAYASHIDA, Kazuhiro ; AMAGAI, Kenji ; SATOH, Keiji ; ARAI, Masataka
概要:
application/pdf<br />Journal Article<br />Spontaneous Raman spectroscopy 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 overlapped 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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| 4.
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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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| 5.
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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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| 6.
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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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| 7.
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茂木, 俊夫 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Fundamental characteristics of the catalytic combustion of vaporized kerosene
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spray were studied experimentally. Palladium catalyst supported on the cordierite honeycomb monolith was used. Inlet temperature was elevated up to 700 K to evaporate the kerosene spray. Premixed gas of air and kerosene vapor was introduced into the catalyst. The catalytic combustion and gas phase reaction after catalyst were observed in this combustion system. The lean limit of the catalytic combustion was not affected by the space velocity and equivalence ratio of the mixture, but it was greatly affected by the inlet temperature. The parabolic shape blue flame that was supported on the catalyst was formed when the supplied mixture was not completely burned in the monolith. To clarify a reaction process in an combustive gas between the monolith and the blue flame, CO, HC(C_1～C_7) and NO were analyzed. When the blue flame was observed after the catalyst, the HC and CO were formed from the unburned composition of fuel and they were burned as the blue flame. The NO emission level of the catalytic combustion was very low compared with the gas phase reaction of lean mixture.
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| 8.
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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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| 9.
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ARAI, Masataka ; HIROYASU, Hiroyuki ; NAKAMORI, Kaoru ; NAKASO, Shinji
概要:
application/pdf<br />Journal Article<br />A new combustion system called a jet-mixing-type combustor was designed to obtain a nonluminous blue flame of a kerosene spray. A spray was injected by a conventional-type swirl atomizer into
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the combustor, and combustion air was introduced through a baffle plate with 16 inlet holes. The principle of this combustion method was revealed as a prompt mixing of the air and spray, which was achieved by high-speed air jets. The combustion characteristics such as combustion stability, temperature distribution and exhaust emissions were compared with a conventional swirler-type combustor. NO and THC emissions exhausted from nonluminous kerosene flame were at lower levels than those exhausted from the swirler-type combustor.
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| 10.
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新井, 雅隆 ; 廣安, 博之 ; 中森, 薫 ; 中曽, 伸二
概要:
application/pdf<br />Journal Article<br />A new combustion system called a jet-mixing-type combustor was designed to obtain a nonluminous blue flame of a kerosine spray. A spray was injected by a conventional-type swirl atomizer into
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the combustor and combustion air was introduced through a baffle plate with 16 inlet holes. The principle of this combustion method was revealed as a prompt mixing of the air and the spray, which was achieved by a high-speed air jet. The combustion characteristics such as combustion stability, temperature distribution and exhaust emissions were compared with a conventional swirler-type combustor. NO and THC emission levels exhausted from nonluminous kerosine flame were lower than those exhausted from the swirler-type combustor.
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