著者

首藤 登志夫 高橋 健洋

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.698, pp.2663-2669, 2004-10-25 (Released:2011-03-03)

参考文献数

13

被引用文献数

8 11

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One of the authors has proposed an HCCI combustion engine system that was fueled with dimethyl ether (DME) with a high cetane number and methanol-reformed gas (MRG) with a high anti-knock property in the previous research. In the system, both DME and MRG are to be produced from methanol by onboard-reformers utilizing the exhaust-heat from the engine. High overall thermal-efficiency has been achieved over a wide operable-range by both the lean HCCI combustion and the waste-heat recovery. While the MRG used in the research was the thermally decomposed methanol, methanol can be reformed to various compositions of hydrogen, carbon monoxide and carbon dioxide. This research aims to find the optimum MRG composition for the system in terms of the ignition control and the overall thermal efficiency. Characteristics of the HCCI combustion of DME and four types of MRG model-gases are experimentaly analyzed. The overall thermal-efficiency was also evaluated for ideal reforming conditions for each case.

著者

阿部 豊 青木 一義

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.71, no.712, pp.2864-2869, 2005-12-25 (Released:2011-03-03)

参考文献数

10

被引用文献数

3

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It is expected to manufacture new materials under the micro-gravity environment in space. Under the micro-gravity environment, holding technology of molten metal is important to manufacture new materials. There are previous studies about droplet levitation by the acoustic wave for the holding technology. However it is still unknown experimentally and analytically how the acoustic wave act on the levitated droplet. In the present study, the technology to handle the material in space by the ultrasonic wave is developed and the simulation technique to evaluate the acoustic wave field and the movement of the droplet in the acoustic field. Therefore the followings are the purposes of present study. At first, the characteristics of droplets holding by the ultrasonic standing wave under normal gravity environment and micro-gravity environment is investigated. Secondary, numerical simulation is conducted to clarity the characteristics of ultrasonic standing wave. Finally, the force committed to a droplet is investigated by reproducing a movement of the droplet.

著者

阿部 豊 青木 一義

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.692, pp.1072-1077, 2004-04-25 (Released:2011-03-03)

参考文献数

4

被引用文献数

1 4

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It is expected to manufacture new materials under the micro-gravity environment. Under the micro-gravity environment, holding technology of molten metal is important to manufacture new materials. In the present study, the technology to handle the material in space by the ultrasonic wave is developed. However, it is difficult to hold a high temperature object by ultrasonic standing wave due to temperature gradient. Moreover, it is also important to measure the physical properties of the material by non-contacting. Therefore the followings are the purposes of present study. At first, the characteristics of droplets holding by the ultrasonic standing wave under normal gravity environment is investigated. Secondly, the surface tension of the droplet is estimated by measuring surface oscillation. Thirdly, the viscous coefficient of liquid droplet is calculated by the damping constant of the droplet. Finally, numerical calculation is conducted to clarity the characteristics of the high temperature object holding in space.

著者

井田 富夫 杉谷 恒也

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.45, no.399, pp.1650-1658, 1979-11-28 (Released:2008-03-28)

参考文献数

19

被引用文献数

1 5

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油中の単一気ほうが急激な圧力変化を受けて膨張・収縮する際の気ほう径と圧力との関係を実験的に調べ、これを理論解と比較してつぎのことを明らかにした。(I)油圧油の基油中では数ms内に1気圧という急激な圧力変化を受ける場合にも、気ほう界面に拡散による相変化が生じる。(ii)基油に微量の界面活性剤を添加すると拡散現象は抑制される。(iii)気ほうの理論解析には表面粘性による界面変形抵抗を考慮する必要がある。

著者

竹村 文男 矢部 彰

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.623, pp.2168-2173, 1998-07-25 (Released:2008-03-28)

参考文献数

15

被引用文献数

5 5

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The gas dis solution process of a spherical rising carbon dioxide bubble in water was investigated experimentally and numerically. We developed an experimental system that use a CCD camera coupled with a microscope to follow the rising bubble. By measuring the bubble size and the rising speed from the bubble motion data captured by a personal computer, we could precis ely estimate the drag coefficients and the Sherwood number for the dis solution of gas bubbles at Reynolds numbers below 100. The experimental results show that the drag coefficients of the carbon dioxide bubble in water show the same value of solid particle even when we use relatively clean water. We also numerically estimated Sherwood number for dis solution of gas bubbles in an infinite liquid by directly solving the Navier-Stokes equation and diffusion equation. The experimental and numerical results are in good agreement. Moreover, we compared the experimental results with a proposed equation for estimating the drag coefficients and Sherwood number and clarified the applicable region of the equation.

著者

田中 皓一 高木 至人

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.58, no.551, pp.2114-2118, 1992-07-25 (Released:2008-03-28)

参考文献数

3

被引用文献数

1 3

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This paper reports the development of a sheet carrying mechanism by means of the progressive wavy motion of a thin elastic membrane which is sustained by magnetic fluid. The sheet carrier consists of a magnetic fluid layer in a shallow rectangular vessel, a thin elastic membrane covering the magnetic fluid, and digital electronic equipment to drive and control a series of magnetic coils. By applying the magnetic field in the form of sinusoidal waves, progressive wavy motions of the magnetic fluid and the elastic membrane are excited, and the sheets of paper or plastic film can be carried on the surface of the membrane. An interesting transportation behavior and its dependence on the wavelength and the frequency of the progessive waves are examined experimentally.

著者

平井 秀一郎 高城 敏美 田中 和洋 来田 憲治

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.53, no.486, pp.p432-437, 1987-02

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Experimental studies have been conducted to investigate the effects of the swirl on the turbulent transport of momentum in a concentric annulus with a rotating inner cylinder. Direct measurements of turbulent transport of momentum were made by correlating fluctuations of two velocity components which were detected by a two-color laser Doppler velocimeter. It was observed that the Reynolds stresses increse due to the swirl. The magnitude of the production terms of the transport equations of the turbulent fluxes of momentum were estimated. The dominating terms are pointed out to illustrate the processes of interactions between momentum fluxes and the swirl.

著者

山崎 徹 曽根 崇正 橋本 崇史 黒田 勝彦

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

巻号頁・発行日

vol.78, no.789, pp.988-992, 2012

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Experimental Statistical Energy Analysis (ESEA) is applied to analyze the vibration energy flow on violin body. The violin body is subdivided into six SEA subsystems. The analysis can identify the power flow through the subsystems and the power input into each subsystem under the impact excitation at the bridge which connects the strings and the body. The analysis results for two kinds of violin are compared. It is shown that three pieces of knowledge regarding better violin are obtained as the followings, 1) damping of the body structure is small, 2) the frequency distribution of power input into the body is in inverse proportion to square root of frequency and 3) the vibration energy on the back plate is propagating only from the top plate through the sound post. The fundamental discussions on the knowledge 2) and 3) are also carried out.

著者

山村 正明 鳥居 平和

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.57, no.543, pp.3695-3700, 1991-11-25 (Released:2008-03-28)

参考文献数

9

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The behavior of an approximate solution of the steady boundary layer equations for two-dimensional incompressible flows is clarified. The moment equations are derived from boundary layer equations as an improvement of the Karman-Pohlhausen method. By means of these results, a simple procedure to construct the boundary layer flow field (including separation flow) with an arbitrarily given retarded outer flow is proposed.

著者

戸嶋 正美 岡村 共由 佐藤 譲之良 宇佐美 賢一 田辺 誠一

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.57, no.539, pp.2186-2191, 1991

被引用文献数

2

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Damage due to the coupled action of silts abrasion and cavitation erosion was experimentally studied using water channel in which artificial silt (Al<SUB>2</SUB>O<SUB>3</SUB>) were included. It was confirmed that the incipient cavitation number in silt laden water increased by 10-15% compared with that in tap water. It was shown that the magnitude of impact pressure measured by the pressure detecting films and casing vibration-acceleration had good correlation with the cavitation erosion intensity but not with the abrasive wear intensity. The damage patterns on aluminum specimens were greatly affected by the cavitation occurrence, but the amount of damaged volume was almost constant with and without cavitation. A ploughing type of abrasive wear was mainly observed on the damaged surface by scanning electron microscope.

著者

竹村 文男 矢部 彰

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.2909-2914, 1997-09-25 (Released:2008-03-28)

参考文献数

10

被引用文献数

1 2

---

Drag coefficients of a spherical rising gas bubble were estimated experimentally and numerically. We developed an experimental apparatus in which a CCD camera with a microscope follows the rising bubble and used it to precisely estimate the drag coefficients of the bubble below Reynolds number of 100 by measurement of the bubble size and the terminal velocity. We also estimated numerically drag coefficients of a gas bubble in an infinite liquid by directly solving a Navier-Stokes equation. The experimental results agree well with the numerical results. Moreover, we compared the experimental results with several proposed equations for estimating drag coefficients and determined the region of applicability of each equation. Finally, we proposed an equation for estimation of drag coefficient by correlating with experimental results.

著者

原田 隆宏 鈴木 幸人 越塚 誠一 荒川 貴博 庄子 習一

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.73, no.726, pp.437-444, 2007-02-25 (Released:2011-03-03)

参考文献数

13

被引用文献数

1 3

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In this study, we developed a code which can calculate three-dimensional micro multi-phase flow using Moving Particle Semi-implicit method. Surface tension which dominates the fluid motion in micro flow also makes the time steps very small and the simulation time becomes very long. We employed a sub-time steps algorithm that enable us stable and efficient calculation of micro fluid with strong surface tension. Using developed code, micro droplet generation in y-shaped micro channel is calculated. We could realize micro droplet generation in our calculation as the same as experiment. In our calculated results, we measured droplet size. The measured droplet size quantitatively agrees with experimental ones. We also visualize flow inside of droplet when a droplet is generated in the calculated results.

著者

矢野 利明 伊藤 献一

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.48, no.431, pp.1392-1401, 1982-07-25 (Released:2008-03-28)

参考文献数

10

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火花点火メタノールエンジンの排気系において, 未燃メタノールの酸化過程には, NOからNO2への変換反応により生成されるOHラジカルが, O2の存在と共に重要であることを, 反応動力学モデルを用いて説明し, 実験結果と対比させた. メタノールの消滅速度は, NO濃度の高い理論当量比付近において最大となる. 一方, ホルムアルデヒド濃度は, O2濃度が高く, しかもNO濃度の低い場合に高くなることが明らかとなった.

著者

橋詰 剛 宮本 武司 赤川 久 辻村 欽司

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.66, no.641, pp.286-293, 2000-01-25 (Released:2008-03-28)

参考文献数

15

被引用文献数

2 1

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By injecting fuel at the very early stage of compression stroke and thus creating homogeneous lean mixture before ignition, (PREDIC;PREmixed lean DIesel Combustion), simultaneous reduction of NOx and smoke was obtained. However, since increasing the mixture equivalence ratio cause knocking, it was difficult to operate at higher load conditions. In this study, in order to reduce combustion rate at high load conditions in a premixed compression ignition engine, multiple stage injection method and EGR were combined, and heterogeneous mixture was made before ignition. The engine test results showed that NOx emissions could be reduced to less than 50 ppm, without knocking even at full load conditions. In addition, smoke emissions were also maintained below invisible level. It can be understood that the premixing of fuel was advanced, smoke was reduced, and EGR rate was increased, resulting lower heat release rate and NOx emissions.

著者

石田 正弘 陳 之立 植木 弘信 山田 武

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.590, pp.3518-3523, 1995-10-25 (Released:2008-03-28)

参考文献数

11

被引用文献数

1

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To reduce the level of exhaust emissions and to improve the ignition characteristics, the effect of pilot injection on combustion was examined experimentally in a turbocharged direct-injection diesel engine, and was analyzed theoretically using a two-zone combustion model. The pilot injection effect was compared with the combustion in the injection without pilot injection and also with the effect of fuel additive as an ignition improver in two kinds of fuel : high-quality fuel having a cetane index of 57 and low-quality fuel having that of 40. It is found that the pilot injection effectively reduces ignition delay at the retarded injection timing, under the low-load condition, and in the case of low-cetane fuel. The ignition delay of the main injection is reduced to about a half of that of the injection without pilot injection by the pilot injection with the short interval between pilot and main injection. The ignition delay of the low-cetane fuel is reduced to that of the high-quality fuel by a small amount of pilot injection, or by adding 1% of the ignition improver.

著者

橋詰 剛 宮本 武司 赤川 久 辻村 欽司

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.66, no.652, pp.3233-3240, 2000-12-25 (Released:2008-03-28)

参考文献数

13

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Simultaneous reduction of NOχ and smoke under high load conditions could be obtained by MULDIC(MULtiple stage DIesel Combustion) where mixture was made stratified before ignition. In this investigation of the basic characteristics of MULDIC, gaseous fuels (DME, Propane) were charged into the intake air which led to the creation of homogeneous lean mixture, and liquid fuel was injected into the cylinder and made rich mixture. The results of the engine test showed that NOχ emissions could be reduced to less than 100 ppm and smoke emissions were also maintained 0 FSN even at higher loads. Moreover, homogeneous rich mixture test results showed that low smoke combustion could be obtained under equivalence ratio of 1.6. In MULDIC, increasing the ignition delay period of injected fuel, soot formation rate was decreased, because over rich region was avoided.

著者

畠沢 政保 杉田 洋 小川 孝廣 瀬尾 宜時

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.70, no.689, pp.292-299, 2004

被引用文献数

31

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A new type of thermoacoustic sound wave generator driven with the waste heat of a 4 cycle automobile gasoline engine is described. The exhaust-pipe connected sound wave generator, in which the hot heat exchanger is set in the exhaust pipe in order to recover the waste heat of exhaust gas, is proposed. A temperature of 780°C of exhaust gas in the exhaust is observed. In a conventional thermoacoustic sound wave generator, sound waves originate at a temperature of the hot heat exchanger, <I>T<SUB>H</SUB></I>, of 200-300°C and become sufficient at 700°C. It is confirmed that the new generator generates sufficient sound waves and its performance is almost equal to that of the electric heater driven generator at a thermal input of 300 W, which corresponds to slightly more than 1% of the heat quantity of exhaust gas provided under the condition that the number of engine revolutions is 2 600 r.p.m. and that the throttle opening is 35%.

著者

近久 武美 湯山 亮 菱沼 孝夫

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.67, no.658, pp.1563-1570, 2001-06-25 (Released:2008-03-28)

参考文献数

11

被引用文献数

5 7

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Investigation on diffusion process is required in variety of field such as chemical reaction, combustion, and environmental studies. However, there is no appropriate index for analyzing degree of homogeneity and scales of the clouds in diffusion field. This paper pressents Entropic Method for determining the homogeneity degree and the scale of the heterogeneous clouds based on the statistic-entropy concept. The results of the investigation on the performance and characteristics of the method showed good correspondence between the analyzed results and the states of the tested pictures. A method for determining a mean effective diffusion-coefficient from the pictures is also discussed. The paper proposes an analitical method available for the study on diffusion phenomena.

著者

吉山 定見 浜本 嘉輔 冨田 栄二 穂積 洋輔

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.626, pp.3479-3484, 1998-10-25 (Released:2008-03-28)

参考文献数

13

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The cross-sectional images of turbulent premixed flames of homogeneous fuel-air mixture in an engine cylinder were obtained by a laser tomography, and the fractal characteristics were investigated. It was observed that in an engine cylinder under high pressure condition, the turbulent flame was a smaller and more complicated structure, comparing with that under the lower pressure condition in a closed combustion chamber. The fractal dimension increases with the increase of the turbulence intensity and mixture density. The fractal dimension is expressed as a function of the increase ratio of mixture density and the ratio of turbulence intensity to laminar burning velocity. The inner cutoff scale of turbulent flames is expressed as a function of Karlovitz number.

著者

青木 克巳 斉藤 昌邦 中山 泰喜

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.51, no.469, pp.p2889-2896, 1985-09

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本論文は旋回流を伴った円筒管内再循環流領域の生成に関して述べたものである.本研究では,レイノズル数1500までに対して,ノズルからの一次流れと旋回器からの二次流れの比,ならびに旋回角の変化に対する数値計算と実験が行われている.そして実験値と計算結果は良く位置している.これらの結果から,流量比,旋回角,レイノルズ数の変化に対する流れ様式を再循環流領域の大きさ,形状などを明らかにした.