著者

野村 信福 中川 勝文

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.59, no.563, pp.2232-2237, 1993-07-25 (Released:2008-03-28)

参考文献数

23

被引用文献数

3 4

---

Ultrasonic enhancement of heat transfer on a narrow surface was measured by changing the width of the surface from 8 to 0.1 mm. Ultrasonic power of 600 W with a frequency of 40 kHz was used. Heat transfer on the narrow surface without ultrasonic vibration was correlated by means of the experimental equation for thin wire. The cavitation intensity was measured by means of the cavitation erosion loss of aluminum foil of 15μm thickness. The effects of acoustic streaming and cavitation were separated by this measurement. Heat transfer by acoustic streaming was predicted through the forced convection. Enhancement by cavitation was explained by the turbulence heat conductivity of the microjets.

著者

野村 信福 中川 勝文

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.59, no.562, pp.2028-2034, 1993-06-25 (Released:2008-03-28)

参考文献数

16

被引用文献数

3 2

---

The cavitation intensity and the heat transfer coefficient on the bottom surface of the object, by applying ultrasonic vibration, were measured experimentally. The object faced the ultrasonic generator adhered to the bottom of the water tank. The dimensions of the object were greater than the ultrasonic wavelength. Ultrasonic power of 600 W with a frequency of 40 kHz was used. The cavitation intensity was defined by the erosion loss of aluminum foil, whose thickness was 15 μm, when aluminum foil stuck on the bottom of the object was immersed into water in the ultrasonic field. The result was that the larger the cavitation intensity became, the more the heat transfer coefficient increased. With varying densities of objects, the greater the density was the larger the cavitation intensity.

著者

岡田 昌章 渡部 康一

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.52, no.473, pp.135-143, 1986-01-25 (Released:2008-03-28)

参考文献数

40

被引用文献数

3

---

工業上重要な熱物性値である各種フロン系冷媒の表面張力に関する実測情報を収集し、比較・検討することにより各県九社の実測値についてその信頼性を評価した。これらの実測値情報にもとづき、17種類のフロン系冷媒について、広い温度範囲にわたり最も信頼し得ると考えられる表面張力値を与える相関式を、核物質に共通の関数形を用いて作成した。さらに、各温度における表面張力値を、その不確かさとともに数値表としてまとめた。

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

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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

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

---

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

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

---

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

三上 真人 嶺山 隆志 伊藤 勝幸 河野 通方

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.3178-3184, 1996

被引用文献数

1

---

The droplet combustion of n-heptane, benzene and ethyl alcohol was investigated in acoustic fields. The frequencies of the acoustic waves used were around the characteristic frequencies of droplet combustion ; the residence frequency and the diffusion frequency. Under low frequency conditions (70-200 Hz), the experimental results can be interpreted by the mechanism of quasi-steady state combustion, which includes all types of droplet combustion ; the envelope name, wake flame and flame extinction. Under high frequency conditions (300-800 Hz), the combustion is possibly influenced by a diffusional mechanism which is induced by acoustic waves of such high frequency.igh frequency acoustic waves increase the flame luminosity, especially for benzene and n-heptane droplets. This suggests that the high frequency acoustic wave enhances radiant heat transfer from the flame zone to the droplet, and thus the burning rate constant increases.

著者

三上 真人 加藤 秀輝 佐藤 順一 河野 通方

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.61, no.582, pp.731-737, 1995-02-25

参考文献数

16

被引用文献数

1

---

The effect of gravity on fuel droplets burning interactively has been studied experimentally. Experiments on two droplets aligned horizontally were conducted both in normal gravity and in microgravity. Results show that in normal gravity, oxygen starvation between the flames is not as severe as in microgravity. Natural convection, which supplies oxygen to the flame, is stronger at a smaller initial separation distance when two flames exist separately. The instantaneous burning rate for the same normalized droplet diameter has a maximum in normal gravity when the initial separation distance is changed and decreases monotonically in microgravity with decreasing initial separation distance, except for the initial period of burning. Thus, the effect of gravity, which decreases the burning lifetime, is greatest at a certain initial separation distance.

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

---

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

三上 真人 加藤 秀輝 佐藤 順一 河野 通方

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.61, no.582, pp.731-737, 1995

被引用文献数

1

---

The effect of gravity on fuel droplets burning interactively has been studied experimentally. Experiments on two droplets aligned horizontally were conducted both in normal gravity and in microgravity. Results show that in normal gravity, oxygen starvation between the flames is not as severe as in microgravity. Natural convection, which supplies oxygen to the flame, is stronger at a smaller initial separation distance when two flames exist separately. The instantaneous burning rate for the same normalized droplet diameter has a maximum in normal gravity when the initial separation distance is changed and decreases monotonically in microgravity with decreasing initial separation distance, except for the initial period of burning. Thus, the effect of gravity, which decreases the burning lifetime, is greatest at a certain initial separation distance.

著者

東野 文男 菊地 英弥

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.49, no.437, pp.115-120, 1983-01-25 (Released:2008-03-28)

参考文献数

2

---

気体と液体の二つの相の領域を考え,気体中で発生した爆風が境界面を通して液体中へ伝ぱする問題を波の干渉を考慮して解析した.解析結果はエクスプローデイング・ワイヤによる実験結果と良く一致し,特に水面上の爆発に対する結果を良く説明できた.また,水中へ透過した圧力波の伝ぱ速度は,水面上で最も強く爆風の影響を受け,ある一定時間後に水の音速まで減衰する.

著者

神保 佳典 高比良 裕之 小林 一道 安田 章宏

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.76, no.762, pp.219-229, 2010-02-25 (Released:2017-06-09)

参考文献数

17

---

The growth and collapse of a bubble under a floating body are simulated by using the boundary element method with linear elements to predict the damage of ship bodies induced by underwater explosion. The three-dimensional deformation of the bubble, the translation and rotation of the floating body, and the motion of water surface are taken into account in the simulation. It is shown that the bubble deforms three-dimensionally, and the liquid jet threads the bubble due to the interactions among the bubble, the floating body, and the water surface; the directions of the bubble translation and the liquid jet depend on the initial location of the bubble. The Kelvin impulse is found to be useful in evaluating the translational motion of the bubble. Also, the horizontal translational motion of the bubble is much dependent on the rotational motion of a floating body; when the moment of inertia of the floating body is small, the largest horizontal translation is realized between the axis of flotation and the edge of the floating body. It is also shown that there exists an initial horizontal bubble location where the moment of force acting on the floating body has the maximum value.

著者

土田 潤 伊東 聰 藤澤 智光 矢川 元基

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.69, no.678, pp.280-285, 2003-02-25

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The sounding mechanism in air-reed instruments is investigated based on the computational fluid dynamics. While previous studies have assumed a sound source based on acoustic theory, the authors attempt in the present study to elucidate exactly the source of sound as an essential factor defining the timbre of musical instruments. To deal with the large computational grids required to capture minute changes in pressure, the Hitachi SR 8000 massively parallel supercomputer is employed for computation. The computational results are consistent with Brown's experimental equation, and new frequency component revealed only in this three-dimensional analysis is identified, attributed to the harmonics of the air jet.

著者

亀本 喬司

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.75, no.760, pp.2349-2351, 2009-12-25 (Released:2017-06-09)

参考文献数

2

著者

里深 信行

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.72, no.718, pp.1385-1387, 2006-06-25 (Released:2011-03-03)

著者

前川 博

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.72, no.724, pp.2845-2850, 2006-12-25 (Released:2011-03-03)

参考文献数

20

著者

千田 二郎 柴田 一郎 藤本 元

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.63, no.613, pp.3179-3186, 1997-09-25 (Released:2008-03-28)

参考文献数

20

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In this paper, propose a new fuel injection system using diesel fuel dissolved in liquefied CO2. The system has the capability of reducing both NOx and soot simultaneously. This concept strives to improve the atomization of fuel spray by flash boiling liquefied CO2 gas. Moreover, it is possible to control the combustion system, for instance, and internal EGR effect is produced by the separated CO2 gas. In this paper, the characteristics of diesel spray of the fuel dissolved with liquefied CO2 were investigated using several optical measurements and the variance of CO2 molar fraction, ambient pressure and ambient density under room-temperature conditions. The spray characteristics were revealed using analysis in chemical thermodynamics. The atomization and dispersion of a free spray composed of fuel dissolved in liquefied CO2 are much better than those of normal diesel fuel oil, due to the flash boiling process in the relatively low pressure field.

著者

川野 大輔 千田 二郎 和田 好充 藤本 元 石井 素 鈴木 央一 後藤 雄一 小高 松男

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.70, no.696, pp.2213-2219, 2004-08-25 (Released:2011-03-03)

参考文献数

20

被引用文献数

1

---

Original KIVA code cannot take account for the spray and combustion processes of multicomponent fuels. Therefore, it is necessary to produce the sub-models for multicomponent fuel using KIVA code. In this study, the modeling of detailed physical properties and evaporation process for multicomponent fuel was conducted. In addition, the effects of fuel composition in multicomponent fuel on vapor distribution, spray tip penetration, vapor mass and evaporation rate, and sauter mean diameter were numerically investigated by using KIVA 3 V code with this multicomponent fuel spray model. From the numerical results, the spray characteristics of multicomponent fuel varied with a change in mixing fraction in multicomponent fuel. Especially, the evaporation of multicomponent fuel was not necessarily improved, even if much amount of high volatility fuel was mixed in the multicomponent fuel.

著者

千田 二郎 錦織 環 北條 義之 塚本 時弘 藤本 元

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.60, no.578, pp.3556-3562, 1994-10-25 (Released:2008-03-28)

参考文献数

23

被引用文献数

2 4

---

This paper presents the model analysis of atomization and vaporization process in a flash boiling spray based on the experimental results. Two kinds of liquid fuel, n-Pentane and n-Hexane, are injected into quiescent gaseous atmosphere at room temperature with low pressure through a pintle-type injector. Then, in flash boiling spray region where the back pressure is below the saturated vapor pressure of fuel, the bubble nucleation process due to flash boiling is modeled by the nucleation rate equation. Furthermore, fuel vaporization process is assessed by considering bubble growth calculations of vapor cavitation phenomena and fuel evaporation due to heat transfer process. Accordingly, we could estimate quantitatively the transient changes in bubble diameter and vapor mass fraction inside the spray for each back pressure condition.

著者

千田 二郎 浅井 崇胤 川口 文悟 藤本 元

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.65, no.632, pp.1459-1466, 1999-04-25 (Released:2008-03-28)

参考文献数

15

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The new injection system by using mixed fuel dissolved with liquefied CO2 was proposed in this paper. Liquefied CO2 was mixed into n-tridecane under pressurized state in order to promote the spray atomization and evaporation due to the effect of the flash boiling phenomena in fuel injection, and to control the combustion process due to the effect of internal EGR effect of CO2 gas. Therefore, the simultaneous reduction of soot and NOx cas be achieved effectively by use of this injection system. In this paper, the characteristics of diesel fuel spray dissolved with liquefied CO2 were investigated quantitatively by means of several optical measurements. And the spray characteristics were revealed by the analysis of chemical thermodynamics. As a result, the atomization of this fuel is promoted due to the flash boiling much more than n-tridecane as the reference of the normal fuel and the spray structure is highly diHerent from that of the normal fuel.Moreover, thenumerical analysis for the atomization and the vaporization process wan carried out based on the flash boiling spray models.