1.

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森田, 真一 ; 渡辺, 直樹 ; 古畑, 朋彦 ; 新井, 雅隆
出版情報: 日本機械学會論文集. B編.  75  pp.1371-1376,  2009-06-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />Six-stroke diesel engine proposed here has six processes in one cycle, i.e. intake, 1st compression, 1st combustion, 2nd compression, 2nd combustion and exhaust. By the direct EGR in the 2nd combustion process, NO emission could be expected to decrease. However, much Soot was exhausted by a weak mixing in the 2nd combustion process. A high pressure injection with a common rail was introduced into the engine to improve the mixing in the second combustion process. As a result, more NO was exhausted while Soot was decreased due to better mixing. In this study, to decrease NO and Soot simultaneously, two stage fuel injection was applied to the 1st combustion. When the main injection timing for the 1st combustion process was extremely delayed, NO and Soot were decreased. It was considered that NO reduction was due to the 1st combustion of low temperature and EGR effect in the 2nd combustion. Also, Soot reduction was due to a relatively long ignition delay for the 2nd combustion 続きを見る
2.

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倉持, 大輔 ; 川口, 知宏 ; 古畑, 朋彦 ; 新井, 雅隆
出版情報: 日本機械学會論文集. B編.  74  pp.469-474,  2008-02-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />Ignition and combustion characteristics of diesel spray impinged on an extrude d wall, which was a top of cylindrical column, were experimentally investigated. Appearance positions of OH and C_2 radical luminosities and luminous flame kernel were stereoscopically observed using a two-way fiber optical system. The extruded column was fixed in a high temperature and high pressure combustion chamber. A diesel spray was impinged vertically to the extruded wall. Effects of cylindrical column diameter (D=5,10,15mm, ∞(flat wall)) on ignition and combustion characteristics were investigated. As the result, appearance position of OH luminosity was observed near the spray tip except for D=∞ (flat wall). The maximum volume of luminous flame impinged on the extruded wall was strongly influenced by the diameter of the column. In a condition of low-ambient temperature, the maximum volume of blue flame on the extruded column of 10 mm diameter was larger than those on other columns. 続きを見る
3.

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小林, 義幸 ; 石間, 経章 ; 小保方, 富夫
出版情報: 日本機械学會論文集. B編.  74  pp.221-227,  2008-01-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />An experimental study on an intermittent fuel spray initiated from a swirl injector proposed for direct injection spark ignition (DISI) engines has been carried out in order to clarify the effects of back pressure and ambient temperature. The measurements have been made in a constant volume chamber in which maximum pressure and temperature reach 1.1MPa and 423K, respectively. Visualization of the spray is performed by a high speed CCD video camera with laser sheet technique. Droplet velocity and diameter are acquired by phase Doppler anemometry (PDA), and processed by a time-dividing method which divides the phase matched spray information into five distinct periods. The effects of ambient temperature on the droplet velocity appear at the tip of the spray. The decrease in Sauter mean diameter D_<32> is observed at core region of the sprays when the ambient temperature is high conditions under both back pressures. 続きを見る
4.

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川口, 知宏 ; 長瀧, 翼 ; 天谷, 賢児 ; 古畑, 朋彦 ; 新井, 雅隆
出版情報: 日本機械学會論文集. B編.  72  pp.1378-1383,  2006-05-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />Ignition and combustion characteristics of diesel spray impinging on a wall were experimentally investigated. Ignition position and appearance position of the luminous flame kernel were stereoscopically observed using a two-way fiber optical system. Flat 続きを見る
5.

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林, 義裕 ; 若林, 千裕 ; 古畑, 朋彦 ; 新井, 雅隆
出版情報: 日本機械学會論文集. B編.  72  pp.1021-1028,  2006-04-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />Mixture formation of diesel spray impinged on an extruded surface, which was a top of cylindrical column, was investigated experimentally. A diesel spray was impinged vertically to the extruded surface. The behaviors of impinged spray were observed using a high-speed drum camera. A spray volume was estimated from the photographs. Effect of cylindrical column diameter on spray behavior was investigated. Adhering fuel was measured by a primitive ""wiping by paper and mass measuring"" method under various conditions. Air-fuel ratio in spray was calculated from spray volume and adhering fuel. As the result, the behavior of diesel spray impinged on an extruded column was strongly influenced by the diameter of the extruded column. From the measured results, it is clear that the air-fuel ratio in spray in the extruded column diameter of 45mm was larger than those in the other columns. 続きを見る
6.

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高, 炅男 ; 樅山, 智裕 ; 新井, 雅隆
出版情報: 日本機械学會論文集. B編.  67  pp.2604-2610,  2001-10-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />Diesel spray impinged normally on a flat wall was investigated. Spray tip penetration and spray volumes of before and after impingement were measured on high speed photographs of the sprays which were injected by a single shot injection system into a high pressure chamber of cold state. The effects of the spray tip penetration, spray volume, entrainment mass and air-fuel ratio were discussed on the sprays of before and after impingement. The volume of the post-impingement spray was calculated using axi-symmetrical model. It was greatly affected by the distance between the injection nozzle and the wall. When the impingement distance was shorter than the break-up length of the original spray, the entrainment mass as well as the volume of post-impingement spray was the larger than that of the original spray at the same inspection time. To calculate the average spray concentration of after impingement spray, the fuel film stuck on the wall was measured. The average air-fuel ratio of the impingement spray increased faster than the free spray because the spray concentration in a space decreased by the fuel stuck on the wall. 続きを見る
7.

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斉藤, 正浩 ; 荻原, 五郎 ; 天谷, 賢児 ; 新井, 雅隆
出版情報: 日本機械学會論文集. B編.  65  pp.920-927,  1999-03-25.  日本機械学会
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 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. 続きを見る
8.

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ISMAILOV, Murad ; DURST, Franz ; OBOKATA, Tomio
出版情報: JSME international journal. Ser. B, Fluids and thermal engineering.  42  pp.22-29,  1999-02-15.  社団法人日本機械学会
概要: application/pdf<br />Journal Article<br />In the present study an LDA-based technique was applied to analyze details of a transient pipe-flow induced upstream by a fuel ingector. Due to highly accurate measurements of the instantaneous time series of velocity, fuel flow rate and pressure gradient were achieved. The pipe flow has been driven under an injection pressure of 0.6MPa at high injection frequencies of 25 and 50 Hz. The influence of the outflow orifice diameter, varid in range from 100 to 500 μm, on the transient pipe flow dynamics has also been described. The results show that transient behavior of rapid oscillating pipe flow is remarkably and systematically dependent on injection frequency and duration as well as on the orifice diameter. 続きを見る
9.

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江原, 拓未 ; 天谷, 賢児 ; 新井, 雅隆
出版情報: 日本機械学會論文集. B編.  62  pp.1253-1259,  1996-03-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />In this paper, behaviors of diesel spray injected along a wall were experimentally investigated. In order to clarify the wall effect on spray structure, the geometry of the wall and its relative position to the spray axis were varied. Structures of spray injected into a high-pressure atmosphere were recorded by high-speed photographs. Results shows that the asymmetrically large vortexes in the spray were induced by the wall effect, and the spray penetrating along the wall was deviated to the wall surface. This phenomenon is called the Coanda effect in the field of fluid dynamics. The growth orientation of spray was defined by image analysis. Maldistribution ratio of spray area was defined for the quantitative estimation of the spray deviation behavior. The spray deviating conditions such as the geometry of the wall and its relative position to the spray axis were fined. 続きを見る
10.

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隆, 武強 ; 石間, 経章 ; 小保方, 富夫
出版情報: 日本機械学會論文集. B編.  62  pp.1260-1267,  1996-03-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />To study the characteristics of velocity in a large-angle conical spray proposed for a premixed combustion type Diesel engine, steady and unsteady conical sprays were analyzed using a laser Doppler anemometer (LDA). The injection pressure for the steady conical spray was varied in three steps. For the unsteady conical spray, it was 19.6MPa, where the amount of injected fuel was 25.6mg per cycle, and the injection frequency was 20.7Hz. As a result, the radial distributions of mean axial-velocity for both conical sprays were similar to the Goertler distribution. The Shapes of the turbulence intensity distributions of the conical sprays and a radial gas jet were similar. Their values for the steady conical spray were smaller than that for the radial gas jet, and those for the unsteady conical spray were almost the same as that for the radial gas jet in the whole experimental region. The Reynolds stress distributions for the steady conical spray and the radial gas jet were similar but the maximum value of steady conical spray was half that of the radial gas jet. The unsteady conical spray had a value of the same order of magnitude as that of radial gas jet in the whole experimental region. The rate of decrease of the unsteady conical spray velocity was 3 times that of the steady conical spray velocity but 1/6 that of the radial gas jet velocity. The rate of air entrainment into the unsteady conical spray was half that for the steady conical spray. 続きを見る
11.

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石間, 経章 ; 小山, 哲司 ; 田中, 秀昭 ; 小保方, 富夫 ; 真下, 亨 ; 小林, 一光
出版情報: 日本機械学會論文集. B編.  61  pp.1935-1941,  1995-05-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />The characteristics of flow and particle diameters in the unsteady spray from an air-assisted fuel injector in atmospheric conditions have been analyzed using a phase Doppler anemometer (PDA). The frequency of injection was 50 Hz, and the pressures of both fuel and air were changed in three steps. Radial and axial distributions of bulk velocity and Sauter mean diameter of spray particles were obtained. It is found from the experiments that the profile of mean velocity is closely related to the normal distribution and the Sauter mean diameter of droplets in the spray is as small as 20 to 30μm. And the log-hyperbolic function (LHF3) has also been applied to the spray. Consequently, the characteristics of the distribution of spray particle sizes are represented clearly by the three parameters of the LHF3. 続きを見る
12.

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論文
高橋, 秀夫 ; 柳沢, 洋樹 ; 志賀, 聖一 ; 柄沢, 隆夫 ; 中村, 壽雄
出版情報: 日本機械学會論文集. B編.  61  pp.351-356,  1995-01-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />The atomization behavior of an intermittent fuel spray from a diesel nozzle was clearly observed by means of shadowgraphy using an image-converting camera with the framing rate of 10^5 f.p.s. and an image-intensified CCD camera with high-speed gating. A rather wide range of valve-opening pressure (5 to 70 MPa) was covered, and simultaneous measurement of the injection pressure inside the nozzle sac was also attempted to clarify the atomization mechanisms at its very early stage of injection. At the beginning of injection, the emergence of a liquid column was observed. Initially, it has almost the same diameter as the nozzle hole and then spreads radially, forming the spray angle in the vicinity of the nozzle exit. The timing of this spray-angle formation becomes earlier with the increase in valve opening pressure, even if the pressure inside the nozzle sac at this moment does not vary. This pressure approximately corresponds to that of the transition region in an atomization regime of a steady jet. 続きを見る
13.

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隆, 武強 ; 大塚, 博行 ; 小保方, 富夫
出版情報: 日本機械学會論文集. B編.  60  pp.2917-2923,  1994-08-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />To study the characteristics of flow and particle diameters in large-angle con ical spray proposed for Diesel engines of premixed combustion, unsteady conical spray in the air has been analyzed using a phase Doppler anemometer (PDA). In experiments, the frequency of injction is 20.8 Hz and the amount of injection fuel is 10.3 mg in each cycle. Axial and radial distributions of bulk velocity and mean diameter of particles are obtained. As a result, it is found that the profile of mean velocity distribution is close to the Goertler distribution, and the Sauter mean diameter of droplets in the conical spray is as small as 30μm. Correlation between particle diameter and velocity in the entire spray is negative and unusual, but is found to be normal if the spray is divided into parts and studied. We also find that particles with small diameter (20μm) which are emitted at high speed (60m/s) at the earliest stage lose velocity rapidly, merge into bigger particles, and are overtaken by bigger but slower particles which are emitted at the later stage. Particles with large diameter (50μm) gather at the tip of the spray as they travel farther from the nozzle exit. 続きを見る
14.

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論文
高橋, 秀夫 ; 柳沢, 洋樹 ; 志賀, 聖一 ; 柄沢, 隆夫 ; 中村, 壽雄
出版情報: 日本機械学會論文集. B編.  60  pp.1093-1098,  1994-03-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />The development of a high-pressure diesel spray in its very early stage is examined through enlarged shadowgraphs in both atmospheric and pressurized conditions. A rather wide range of valve opening pressure was covered to clarify the mechanisms of the initial stage of development. At 0.3 ms after the start of injection, there is a region where the tip penetration is insensitive to the ambient pressure and it becomes shorter with the increase in valve opening pressure. This characteristic feature of the spray formation process is related to the eddy motion generated in the spray. The transition of the atomization regime from a wavy jet to a fully developed spray is also shown, and it is suggested that the pressure history in the nozzle sac is closely related to this phenomenon. 続きを見る
15.

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論文
細谷, 肇 ; 小保方, 富夫
出版情報: 日本機械学會論文集. B編.  59  pp.2897-2905,  1993-09-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />There have been many experiments to characterize Diesel fuel spray under steady-state conditions. However, the appropriate number of holes and the hole position on the sac to be used in the experiment are not clear. To address this subject, we investigate Diesel type spray flows using a laser Doppler anemometer (LDA) and a phase Doppler anemometer (PDA). Spray flow characteristics such as mean and fluctuating two-component velocities, two-dimensional distribution of particle diameter and the variation of three parameters at the log-hyperbolic fitting for particle size distribution are given from measured data. Spray jets from four varieties of Diesel nozzle are compared with each other to clarity the differences in spray characteristics between them. The results show that the spray from the single-hole nozzle on top of the sac is distinct from the others. 続きを見る
16.

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小田, 哲也 ; 廣安, 博之 ; 新井, 雅隆 ; 西田, 恵哉
出版情報: 日本機械学會論文集. B編.  58  pp.2595-2601,  1992-08-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />To elucidate the atomization process of a liquid jet across a high-speed airstream, the spray shape, the mass flow rate per unit area and the Sauter mean diameter were measured. Under an airstream velocity of 140m/s or 70m/s and injection velocity of 10m/s, 20m/s or 40m/s, the Sauter mean diameter and the maximum liquid mass flow rate per unit area in the spray hardly changed with the liquid injection velocity. However, with increasing air velocity, the Sauter mean diameter decreased and the maximum liquid mass flow rate per unit area increased. Rearranged spatial distribution of the liquid mass flow rate per unit area in a horizontal direction agreed with the profile by the Gauss's function. An equation for width of spray was obtained from the photographic results. 続きを見る
17.

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小田, 哲也 ; 廣安, 博之 ; 新井, 雅隆 ; 西田, 恵哉
出版情報: 日本機械学會論文集. B編.  58  pp.2602-2606,  1992-08-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />To elucidate the atomization process of a liquid jet across a high-speed airstream, the spatial distribution of liquid, drop diameter and drop trajectory were calculated. In this model, a liquid column is not incorporated. Drops ejected from the injector have the same velocity V_l but different drop diameters, which are defined by the volume distribution of drop size. The ejected drop is broken up by the airstream. Calculated spatial distribution of liquid agrees well with measured spatial distribution of liquid. The trend of the calculated drop diameters agreed well with the trend of the measured Sauter mean diameter. The drop diameter decreases rapidly, near the injector especially along the outer line of the spray. 続きを見る
18.

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細谷, 肇 ; 小保方, 富夫
出版情報: 日本機械学會論文集. B編.  58  pp.1252-1258,  1992-04-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />Diesel fuel spray from a single-hole-type injection nozzle is investigated under steady and atmospheric conditions in order to understand the unsteady Diesel spray. Axial and radial velocity components of the spray at two constant injection pressures of 9.8MPa and 4.9MPa are measured by laser Doppler anemometer (LDA), and turbulence characteristics of the spray flow velocities are analyzed. Distributions of mean velocity and turbulence characteristics in the spray flow are compared with gas jets and other spray flows. It is found that the injected spray is accelerated in the region close to the nozzle exit, and this phenomenon may be estimated as a kind of cavitation caused by expansion of dissolved gas in the fuel. The decrease in centerline velocity along the nozzle axis is very small and the air entrainment factor is also shown to take a smaller value than in previous experiments. 続きを見る
19.

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TABATA, Michihiko ; FUJII, Hiroshi ; ARAI, Masataka ; HIROYASU, Hiroyuki
出版情報: JSME international journal. Ser. 2, Fluids engineering, heat transfer, power, combustion, thermophysical properties.  34  pp.369-378,  1991-08-15.  社団法人日本機械学会
概要: application/pdf<br />Journal Article<br />The Sauter mean diameter and size distribution of a diesel spray in a vaporizing process were studied to obtain detailed information of the diameter change of the spray in an elevated-temperature and-pressure environment. In this study, direct photographs of the diffracted light from particles or spray drops were taken using a pulsed laser and analyzed directly. The mean particle size could be measured even if the diffracted light from particles passed through a high-ambient-temperature and-pressure environment. The liquids used for studying a vaporizing diesel spray were diesel fuel and n-heptane. The Sauter mean diameter increased to a maximum, then decreased with a further increase of the ambient temperature. The change of the Sauter mean diameter was different for different fuel evaporation rates. The increase of the Sauter mean diameter of n-heptane spray occurred at a lower ambient temperature condition than did that for the diesel spray. 続きを見る
20.

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論文
清水, 正則 ; 新井, 雅隆 ; 廣安, 博之
出版情報: 日本機械学會論文集. B編.  56  pp.2519-2525,  1990-08-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />In order to elucidate the disintegrating mechanisms of a diesel spray, the breakup length was measured by an electric resistance method. A reattachment distance of separated liquid flow in a nozzle and a spray were observed photographically. The mechanism of the two disintegrating processes of the jet was investigated by separating an ambient effect from a disturbed effect of the nozzle. The atomizing mechanism of the jet was governed by both the initial disturbance due to the nozzle geometry and an interfacial force between the jet and the environment. If a strong disturbance was given to the internal flow in a nozzle, the jet would be broken up into a spray flow. 続きを見る
21.

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高橋, 秀夫 ; 志賀, 聖一 ; 小柴, 英俊 ; 柄沢, 隆夫 ; 倉林, 俊雄
出版情報: 日本機械学會論文集. B編.  56  pp.1837-1842,  1990-06-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />The purpose of this study is to clarify the characteristics of diesel spray with higher and unsteady injection pressure under an elevated pressure condition and an elevated pressure and temperature condition. A Bosch-type injection system and a rapid compression machine were used. The behavior of the spray until 2 ms after the beginning of injection, which corresponds to the period of the ignition delay of most diesel engines, was observed by high-speed photography. Under the less evaporating condition, the spray penetrations of higher and normal injection pressure are almost the same, whereas, under the evaporating condition, those penetrations are not the same. Thus, the penetration of the normal injection pressure is affected by the ambient temperature, while the penetration of the higher injection pressure is little affected by the evaporation. The same tendency was observed in the behavior of spray cone angle development. It is also shown that the spray generates small eddies and the spray pattern is affected by the growth and dissipation of those eddies. 続きを見る
22.

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高橋, 秀夫 ; 志賀, 聖一 ; 柄沢, 隆夫 ; 倉林, 俊雄
出版情報: 日本機械学會論文集. B編.  56  pp.1218-1221,  1990-04-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />A rapid-compression machine is developed for fundamental studies of diesel combustion. Low-pressure compressed air and a stainless-steel membrane are employed to drive the piston. This is similar to the principle of a shock tube and is quite simple compared with other machines. The combustion chamber has a 120 mm bore and is 20 mm in depth. These dimensions were determined to avoid the impingement of the spray within 2ms, which seems to be a typical ignition delay period. Compression time and polytropic exponent are about 38ms and 1.30, respectively. High-speed photographs were taken to observe the spray development for both evaporating and non evaporating spray, and the effect of evaporation could be shown clearly. A combustion test was also carried out, and a pressure rise due to combustion was recognized. Thus, it is shown that this machine has sufficient performance for the study of diesel combustion. A simple simulation technique to design the machine is also presented and its availability is verified. 続きを見る