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| 1.
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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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| 2.
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佐藤, 博之 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Flame lengths of gas jet diffusion flames were measured under various gravity
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evels. A spin tester was used to obtain a high gravity field which level was changed from normal gravity (G=1) to G-20. In order to investigate the fuel density effect on flame structure at high gravity level, two kinds of fuels (methane and propanw) and further methane-propane mixture fuel whose density was equivalent to the surrounding air were used. As the results, flame length decreased with an increase of gravity level regardless of the positive and negative buoyancy effect between the fuel and surroundings. To investigate the gravity effect on flame structure, length of blue flame which appeared at anchor portion of the flame was measured under various gravity levels. It was confirmed that the blue flame was expanded with an increase of the gravity level. This result was explained by the enhancement of the air entrainment at the anchor portion of the flame. Evaluation of flame length which was obtained by Altenkirch considering the relationship of fuel and required oxygen were used to evaluate the experimental data of flame length under the various gravity level. From this method the following empirical correlation was proposed : L_f/γ_o=1.72Re^<0.667>Fγ^<0.0846>, where L_f is a flame length, γ_o is a nozzle radius, Re is the Reynolds number based on nozzle radius and Fγ is the Froude number.
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| 3.
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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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| 4.
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斉藤, 正浩 ; 荻原, 五郎 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Behavior of spray-to spray impingement, where two spray jets were formed EFI (Electronic Fuel Injection) nozzles and impinged each other, was studied experimentally. This system was
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named MISS EFI. Spray penetration and the Sauter mean diameter of the spray were measured to investigate the effect of spray-to-spray impingement. When the impingement location was set at the vicinity of the nozzles, impingement phenomena became to be jet to jet impingement of the liquid column. In this condition, the penetration became shorter than that of the individual penetration. However, the penetration did not changed after spray-to-spray impingement. From the photographs of jet-to-jet impingement, it was confirmed that the liquid film was formed by the impingement, and then this liquid film disintegrated to small droplets. In the spray-to-spray impingement, on the other hand, the relatively large droplets still existed in the impinged spray, because the two sprays crossed each other without disintegration of the droplets. The photograph of the spray-to-spray impingement showed that the droplet-to-droplet impingement in the spray was rarely observed. Further, the chance of coagulation of the droplets was less observed than the disintegration of the dropled. These behavior of the spray-to-spray impingement agreed with the reduction of the Sauter mean diameter of the impinged spray.
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| 5.
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伊東, 明俊 ; 天谷, 賢児 ; 新井, 雅隆 ; 三舩, 博史
概要:
application/pdf<br />Journal Article<br />This paper experimentally investigates a behavior of a bioconvective pattern under super gravitational fields. Experimental materials are the high density culture media of Tetrahymena. A
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centrifugal force was used to synthesize various super gravity conditions by using a spin tester that can generate 1-12[G]. To realize the decreasing effect of bioconvection pattern size by the increase of synthesized gravity, different lengths of a rotative beam are used to change the rate of Corioli's force and synthesized gravity. The main results are as follows: (1) The size of the convection pattern is reduced by an increase of the synthesized gravity. (2) Under synthesized gravitational field, the stream mode of bioconvection is changed by the Corioli's force. (3) The maximum transition velocity (upward, downward) of Tetrahymana is obtaind with the 2-4[G] condition. (4) The decrease in the size of convection pattern is due to the composite gravity.
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岡本, 雄一郎 ; 荻原, 五郎 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />A six-stroke diesel engine which was proposed by authors had second compression and second combustion strokes which were added on a four-stroke diesel engine. Numerical prediction and experiments
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on six-stroke engine which were carried out previously, showed that a six-stroke diesel engine could reduce NO concentration and shorter ignition delay could be attained in second combustion. Using various fuels on second combustion, it might be possible to improve more the emission characteristics. In this report, Methanol was used in the second combustion to improve the six-stroke engine performance. As the result, NO concentration in the exhaust gas decreased with delaying of the injection timing at second combustion and increased with an increase of the heat allocation ratio of second combustion stroke when the injection timing at first combustion stroke was fixed. Smoke wasn't exhausted at all when Methanol was put into the second combustion stroke. NO concentrations were affected by the heat allocation ratio and related with gas temperature. It was confirmed that the NO concentration of the Diesel fuel-Methanol engine become lower compared with that of the Diesel fuel engine.
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| 7.
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新居, 利洋 ; 斉藤, 正浩 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />This paper reports the suppression of soot emission from acetylene diffusion flame by applying electric field. The effects of applied voltage, polarity and spacing of electrodes on soot emission
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were investigated experimentally. The results showed that the shape of flame changed and the soot emission decreased with increasing the applied voltage. The polarity of applied voltage influenced to the shape of flame and the soot emission. When positive voltage was applied to the nozzle electrode, the flame length became short and the width at the flame tip was spread. And, more than 90% of soot emission was suppressed at over 200 kV/m of the intensity of electric field. The surface temperature of flame increased with increasing the applied voltage. Thus, it was considered that the increase of flame surface temperature promoted the soot oxidation. When negative voltage was applied to the nozzle electrode, on the contrary, only the 70% of soot emission was suppressed, because the flame temperature was comparable to that for non-applied voltage.
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| 8.
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江原, 拓未 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />In the previous paper, the authors clarified that an impingement spray have the slip flow region near the impingement point on the wall. Then, behavior of a diesel spray impinging on an
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inclined wall was modeled to make an empirical formula of impingement spray tip penetration. To introduce a new model of spray growth behavior, uniform velocity penetration of the spray growth behavior in the slip region were framed and included into the traditional formula about the free spray. The momentum conservation theory was applied to the spray of after slipping. The growth behavior of an impingement spray was expressed as the function of wall distance and inclined wall angle. Spray path length calcurated from this formula showed qualititaively well agreement with an actual measurement.
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| 9.
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論文
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岡本, 雄一郎 ; 荻原, 五郎 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />A Six-stroke diesel engine was developed and its performance was evaluated. This engine had second compression and second combustion strokes which were added on the four stroke diesel engine.
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To control the fuel injection ratio and injection timings for first and second combustion strokes independently, two fuel pumps were attached to the engine. Effect of the fuel allocation ratio between first and second combustion strokes on the engine performance was investigated. Engine performance of the six stroke diesel engine was compared with that of the four stroke diesel engine which was the base engine of the six stroke engine. As a result, NO concentration in the exhaust gas decreased with a delaying of injection timing at second combustion stroke, but the injection timing at first combustion stroke didn't influence NO concentration. NO concentration decreased with an increase of allocation fuel ratio into the second combustion stroke. A trade-off relation between NO and soot concentration was observed against the change of allocation ratio. From the comparison between six and four stroke engine, it was confirmed that the NO concentration of the six stroke engine becomes lower than that of the four stroke engine.
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| 10.
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江原, 拓未 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />In this paper, behavior of a diesel spray impinging on an inclined wall was experimentally investigated in a pressurized vessel. In order to clarify the wall effect on a diesel spray
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structure, a relative angle of the inclined wall to the spray axis was varied. Spray penetration along the wall was observed optically and compared with that of a free spray. To observe an internal structure of the spray, it was visualized by a YAG laser sheet light and its tomographic image was captured on a film. The photo-image on a film was taken into an image analyzing computer using a high resolved image scanner. High density ridges in the tomographic image were extracted to clarify the internal structure of an impingement spray. Further, the growth characteristics of impingement spray was observed by a high speed photograph. To evaluate various spray motion quantitatively, a spray path penetration which described a development of a spray tip along the wall was used. As the result, the slip flow region of spray was found near the impingement point on the wall. It seemed that the injected fuel does not make a mixture and slipped on the wall surface in this slip region. The length of this region was measured in various impingement wall condition.
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