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林田, 和宏 ; 土師, 勝彦 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />In this study, effect of fuel properties on diffusion combustion of kerosene was investigated experimentally. Five types of kerosene, which distillation and composition properties were
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different, were used as the test fuel. Laminar diffusion flames of kerosene were formed by using wick combustion burner. Fuel consumption rate, flame temperature and flame luminosity of each flame were measured. As the results, fuel consumption rate proportionally increased with decreasing volume average boiling point, and both temperature and luminosity decreased as the aromatic content in the fuel increase. To investigate the effect on soot formation of fuel properties, concentration distributions of polycyclic aromatic hydrocarbons (PAHs) and soot were measured by laser-induced fluorescence (LIF) and laser-induced incandescence (LII). Both PAHs-LIF intensity on wick and LII intensity of soot emission increased with the content of aromatic compounds in the fuel became higher.
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| 2.
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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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| 3.
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佐藤, 桂司 ; 林田, 和宏 ; 宮川, 拓 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Laser induced fluorescence (LIF) method was applied to the measurement of PAHs (Polycyclic Aromatic Hydrocarbons) in a propane diffusion flame. Various PAHs were excited by a KrF excimer laser
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and a dye-laser pumped by the XeF excimer laser. By measuring the enission spectra of various PAHs vapors, it was found that the peak wavelength in the emission spectrom of LIF shifted to the longer wavelength side with an increase of PAHs carbon numbers. The carbon numbers of PAHs in a diffusion flame was presumed from the data of peak wavelength of emission spectrum. It was confirmed that the carbon numbers of PAHs in the diffusion flame increased as approaching to the flame surface. The maximum carbon number was about 26 at the layer close to the flame surface.
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| 4.
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林田, 和宏 ; 天谷, 賢児 ; 白井, 紘行 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />LIF thermometry in a sooting diffusion flame was newly proposed based on a spe
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ctral matching method. A tunable ArF excimer laser was used to excite the several absorption lines in the D^2Σ^+←X^2II(0, 1) band system of NO. In the case of sooting diffusion flame, emission spectrum consisted of NO and O_2 fluorescence, and off-resonance emissions related to the soot. The O_2 fluorescence and the off-resonance emissions overlapped on the NO fluorescence. However, the offresonance emissions near the vacuum ultraviolet region (VUV) were weaker than the NO fluorescence, and the ε(0, 3) band of the NO fluorescence, which appeared near the VUV region, was free from the O_2 fluorescence. Therefore, NO rotational temperature in a sooting diffusion flame could be measured by the spectral matching method using the ε(0, 3) band. By using this technique, NO rotational temperature in a propane diffusion flame could be measured.
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| 5.
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論文
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佐藤, 桂司 ; 林田, 和宏 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />In this paper, separation of laser-induced fluorescence (LIF) due to PAHs and incandescence (LII) due to soot by time-resolved measurement was demonstrated for the propane diffusion flame.
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Laser-induced fluorescence method for the measurement of polycyclic aromatic hydrocarbons (PAHs) in diffusion flame was developed. A KrF excimer laser was used for excite the PAHs. Strong laser-induced incandescence due to soot was appeared with fluorescence signal due to PAHs. In order to separate the signals into LII and the PAHs-LIF detected from diffusion flame, time-resolved measurement was carried out. A pico-second gate CCD camera with a image intensifier was used taking a time-resolved image. From the two different images, which were taken at different time-delay, PAHs-LIF and LII were obtained. Intensity distributions of PAHs-LIF and LII were measured on the flame axis. Overlap region of the LIF and LII was observed around the onset position of the yellow flame. In this region, LIF intensity decreased and LII intensity increased along the flow direction. It seemed that this region was transition region from the PAHs to soot and was attributed the presence of soot precursor.
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| 6.
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林田, 和宏 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />NO concentration measurement in the burnt gas from the catalytic combustion was carried out by using a laser-induced fluorescence method. A palladium catalyst supported on a cordierite honeycomb
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was used. The methance/air mixture, which was pre-heated to 530 K, was introduced into the catalyst honeycomb. To excite a NO molecule, an ArF excimer laser was used. Wavelength of the laser right was set at 193.375 nm. The laser sheet was introduced into the downstream of the honeycomb. In the case of a lean mixture, NO was observed after the honeycomb. On the other hand, in the case of a rich mixture, a blue flame at downstream from the honeycomb were observed, and NO was observed at the blue flame. In order to obtain the NO concentration from the NO fluorescence intensity, temperature dependency of the fluorescence intensity was investigated by using NO-N_2 mixture. Axial concentration distributions of NO were derived from the NO fluorescence intensity distributions. Furthermore, change of the NO emission level with equivalence ratio was investigated at the outlet of the honeycomb.
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| 7.
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林田, 和宏 ; 白井, 紘行 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Rotational temperature of NO molecule in methane/air premixed flame was estima
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ted by a spectral matching method. A tunable narrow band ArF excimer laser was used to excite the D^2Σ^+(ν′=0)←X^2Π(ν""=1) band system of NO. Laser beam irradiated a flame, and the laser induced fluorescence was resolved into a spectrum by using a spectroscope. On this spectrum, ε and δ bands of upper vibrational level of ν′=0 were analyzed. In order to use a spectral matching method, profiles of ε and δ band spectra were calculated theoretically in detail with reliable molecular constants and exact formula, and they were modulated by an experimental slit function. Since the profile of band spectrum was determined as a function of a rotational temperature, a rotational temperature could be estimated from the temperature where the profile of every band spectrum obtained theoretically is fitted to that of experimentally obtained. Applying a spectral matching method on the ε(0, 3), ε(0, 4) and δ(0, 2) band of NO, it was obtained that the rotational temperature is about 1000K. Obtained rotational temperature is almost agreed with a thermocouple temperature.
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| 8.
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林田, 和宏 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Laser induced fluorescence was applied for the measurement of OH concentration
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in the propane diffusion flames. A tunable, narrow band KrF excimer laser was used to excite the A(ν'=3)←X(ν""=0) band of OH radical. An emission spectrum of the induced light from the flames was measured by a spectroscope. An OH fluorescence component was picked up from the emission spectrum in order to obtain the accurate distribution of OH fluorescence in the flames. We call this method for spectrum-LIF (S-LIF). The spectrum of the induced light from the diffusion flames was compared with that of the premixed flames. Although the spectrum had only OH fluorescence components in the case of premixed flames, high intensity emission from the yellow flame appeared on the LlF image in the case of diffusion flames. To remove the high intensity emission from the LIF image, off resonance image was deducted from the OH resonance image as the background image. Using this deduction method, a planer laser induced fluorescence (P-LIF) was tried to measure the distribution of OH fluorescence. OH fluorescence distribution measured by P-LIF was compared with that of S-LIF. As the result, the P-LIF image qualitatively agreed with the data of S-LIF.
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