著者

劉 本柱 三上 真人 小嶋 直哉

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集B編 (ISSN:03875016)

巻号頁・発行日

vol.62, no.600, pp.3220-3226, 1996

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The flow induced noise from an expansion cavity-type muffler increases abruptly for some sizes of mufflers and flow velocities. This phenomenon is strongly related to the resonance of the tail pipe and the cavity of the muffler ; therefore, it is called the predominance of resonance″When the cavity length is increased, the measured resonance frequency shows periodic jumps. The cause of the predominance of resonance is assumed to be the generation of vortex rings with a particular frequency in the cavity. The generation of vortex rings is verified by analyzing fluctuating velocities in the cavity when the predominance of resonance occurs. The phenomenon is induced not only by the tail pipe resonance, but also by the cavity resonance. It is suggested that there exists the feedback phenomenon from the sound to the flow and it is strongly related to the sound pressure level in the cavity.

著者

劉 本柱 三上 真人 小嶋 直哉

雑誌

日本騒音制御工学会技術発表会講演論文集

巻号頁・発行日

vol.1995, pp.205-208, 1995-09

参考文献数

4

著者

相本 幸宏 池田 光優 三上 真人 小嶋 直哉

出版者

一般社団法人 日本機械学会

雑誌

中国四国支部総会・講演会 講演論文集

巻号頁・発行日

vol.2002, pp.107-108, 2002

著者

池田 光優 三上 真人 小嶋 直哉

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集B編 (ISSN:03875016)

巻号頁・発行日

vol.64, no.625, pp.3126-3132, 1998

被引用文献数

1

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Attempts have been made to improve exhaust gas characteristics of the direct injection diesel engine under dual-fuel operation with gas oil and LPG. In dual-fuel operation with LPG as a sub-fuel, two kinds of LPG mixing methods can be employed. One is LPG mixing in gaseous state with the intake air, which is so-called "fumigation". The other is LPG mixing in liquid state with gas oil prior to injection. The experimental results show that the mixing method in liquid state is better than the fumigation method in terms of NO and THC emission and specific energy consumption. In the mixing method in liquid state, NO is reduced in comparison with the base engine without the increase in THC, smoke and specific energy consumption if a proper squish intensity is employed.

著者

和泉 晴夫 三上 真人 小嶋 直哉

出版者

山口大学工学部

雑誌

山口大学工学部研究報告 (ISSN:03727661)

巻号頁・発行日

vol.49, no.1, pp.1-6, 1998-10

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気流を伴う消音器内で発生する気流音の特性は,流速や消音器構造に複雑に依存しており,共鳴音を含め音響学的解明は不十分である。本研究は,気流音の発生メカニズムを従来の研究よりさらに深く洞察するために,実験的に空胴部共鳴周波数と尾管部共鳴周波数の間に移行現象があることを認めたので,理論的考察の一方法として四端子定数で厳密計算し,周波数移行現象の予測と実験との対応を行い,発生機構の整理を行った。

著者

劉 本柱 三上 真人 小嶋 直哉

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.62, no.600, pp.3220-3226, 1996-08-25

参考文献数

11

被引用文献数

2

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The flow induced noise from an expansion cavity-type muffler increases abruptly for some sizes of mufflers and flow velocities. This phenomenon is strongly related to the resonance of the tail pipe and the cavity of the muffler ; therefore, it is called the predominance of resonance゛When the cavity length is increased, the measured resonance frequency shows periodic jumps. The cause of the predominance of resonance is assumed to be the generation of vortex rings with a particular frequency in the cavity. The generation of vortex rings is verified by analyzing fluctuating velocities in the cavity when the predominance of resonance occurs. The phenomenon is induced not only by the tail pipe resonance, but also by the cavity resonance. It is suggested that there exists the feedback phenomenon from the sound to the flow and it is strongly related to the sound pressure level in the cavity.

著者

倉橋 吉則 三上 真人 小嶋 直哉

出版者

一般社団法人 日本機械学会

雑誌

中国四国支部総会・講演会 講演論文集

巻号頁・発行日

vol.5, pp.109-110, 2000

著者

三上 真人 大八木 大史 小嶋 直哉 菊池 政雄 若嶋 勇一郎 依田 真一

出版者

一般社団法人 日本燃焼学会

雑誌

日本燃焼学会誌 = Journal of the Combustion Society of Japan (ISSN:13471864)

巻号頁・発行日

vol.45, no.134, pp.238-247, 2003-11-30

参考文献数

30

被引用文献数

3

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<p>A new concept of the droplet array generation technique was proposed to realize a high quality and high reliability performance of microgravity experiments of multiple-droplet combustion. Each fuel droplet was formed on the intersection of the X-shape fine SiC fibers by supplying the liquid fuel through a fine glass tube. Several sets of the X-shape fibers and corresponding fine glass tubes were aligned at an interval to make a droplet array. All the droplets in array were simultaneously generated in a short time. In flame spread experiments, an end-droplet was ignited by a hot-wire igniter to initiate the flame spread along the array. Microgravity experiments of droplet array combustion were demonstrated with the new droplet array generation technique using a drop experiment facility MGLAB in Japan. In microgravity, large droplets, which were often failed to be generated in normal gravity, were successfully generated through this method. The present technique is also effective in droplet array combustion experiments using a high-volatility fuel, whose prevaporization is not negligible. The flame spread rate and the flame spread limit of linear droplet arrays were compared with existing experimental results. Effects of the suspending fiber on the flame spread were also discussed.</p>

著者

三上 真人 八木 孝 小嶋 直哉

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集B編 (ISSN:03875016)

巻号頁・発行日

vol.64, no.624, pp.2690-2695, 1998

被引用文献数

2

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Occurrence behavior of microexplosion in droplet combustion of fuel mixtures is studied. Experiments were performed using unsupported droplets of n-alkane/n-hexadecane mixtures in normal gravity. It was found that the occurrence of microexplosion is stochastic and cannot be predicted by the classical criterion for microexplosion occurrence using the limit of superheat and the droplet temperature. An occurrence model for the microexplosion based on the homogeneous nucleation theory is presented and shows that the occurrence probability of the microexplosion is determined by the ratio of the liquid phase lifetime to the nucleation time during the quasi-steady vaporization period. The nucleation time is inversely proportional to the nucleation time is inversely proportional to the nucleation rate and superheated liquid volume. The relative value of the droplet temperature and the limit of superheat affects the occurrence probability through the nucleation rate. It can be well explained by the model that the occurrence probability has the maximum value for a certain initial concentration of the fuel mixture.

著者

小林 啓二 小嶋 直哉 福田 基一

出版者

山口大学工学部

雑誌

山口大学工学部研究報告 (ISSN:03727661)

巻号頁・発行日

vol.34, no.2, pp.p225-231, 1984-03

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An anechoic room for engine noise test was constructed. In constructing it, the sound absorbing wall with its supporting structures was carefully designed because their strong influence on the performance of the anechoic room. The back ground noise, the inverse square law and the mean absorption coefficient of this room were examined in detail. From these experimental results, it was confirmed that this anechoic room showed the sufficient characteristics for the experimental researches on noise generation from running engines.

著者

劉 本柱 岡 智弘 三上 真人 小嶋 直哉

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.63, no.611, pp.2500-2506, 1997-07-25

被引用文献数

1

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Predominant resonance can occur in flow-induced noise from an expansion-cavity-type muffler for particular combinations of muffler configuration and flow velocity. This phenomenon is caused by self-excited oscillation based on the feedback response from acoustic resonances of the muffler to shear flow. Usually, the sound pressure level is much higher when predominance of tail pipe resonance rather than cavity resonance occurs. The predominance of tail pipe resonance is shown to be strongly influenced by both the frequency characteristics of acoustic amplification of the tail pipe and the frequency of velocity fluctuation with a certain phase criterion. The predominance phenomena can be generalized using a new dimensionless independent variable, (L/l')(1/M), where L, l' and M are cavity length, acoustically equivalent tail pipe length and Mach number in the tail pipe, respectively.