著者
吉川 大雄 菱沼 孝夫 近久 武美 早坂 厚
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 = Transactions of the Japan Society of Mechanical Engineers. B (ISSN:03875016)
巻号頁・発行日
vol.68, no.665, pp.218-223, 2002-01-25
参考文献数
12
被引用文献数
2

The objective of this study was to estimate the optimization of fuel cell electric vehicle systems by the driving simulation that we developed. The results of the driving simulation showed the power of fuel cell, battery and motor for a 1 500 cc class sedan is 12, 18 and 15 kW at the condition of 10-15 mode of the minimum fuel consumption. The fuel consumption of the series driving system of FCEV was more than the parallel because of the heavier vehicle weight of the series compared to the parallel. The numerical analysis showed that the FCEV performance is affected by the regenerative brake and the fuel consumption of the FCEV with the regenerative brake systems is 23% less than without them.
著者
辻川 吉春
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.54, no.501, pp.1207-1212, 1988-05-25

The characteristics of LACE, or a liquid air cycle engine, for hypersonic airbreathing propulsion is discussed. Both air and hydorgen are pumped up to a high pressure in the liquid phase; the liquid air and gaseous hydrogen from the heat exchanger (air condenser) are burned in a rocket chamber and are expanded in a normal propelling nozzle. With the speed range up to a Mach number of 10, LACE can be found to maintain its superiority over the rocket concering the specific impulse.
著者
棚橋 隆彦 沖 良篤
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.568, pp.3823-3830, 1993-12-25 (Released:2008-03-28)
参考文献数
12

In this paper, we present a new hybrid-streamline-upwind finite-element method, which is based on the finite analytic method developed in the field of the finite difference method. In order to obtain an optimal shape function, we introduce an adjoint differential operator to the differential operator for a steady advection-diffusion equation. The shape functions which satisfy these differential operators are mutually dual. One of them interpolates accurately the functions appearing in convection-dominated flows, the other becomes a hybrid-streamline-upwind weight function. Furthermore, we define a discrete del operator for the reduction of memory storage in the computer. As a result, we achieve simplicity of formulation and high-speed calculation of the finite-element method.
著者
越後 亮三
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.435, pp.2315-2323, 1982
被引用文献数
9

適度の光学的厚さをもつ多孔性の通気性大層を高温の作動ガスが横切って流れるとき大きなエンタルピ落差が生じ, ふく射エネルギに変換され, その主要部が流れの上流方向に伝般する新しい伝熱系に関し理論解析と基礎実験を実施した. 本原理は応用範囲も広く, 工業用路に適用すると設計の基本概念を変革するほどの大きな効果が期待でき, 小型金属加熱炉の実験を行った結果, 60%もの燃費節減ができた.
著者
中野 晋 内田 剛 石ヶ森 勲 菅原 敏 新田 慶治
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.64, no.617, pp.107-114, 1998-01-25
参考文献数
9

It is necessary to develop a small positive pressure control system for the closed ecology experiment facilities because of the needs to prevent contamination from the atmosphere and to protect against over differential pressure loading. In the present study, a numerical analysis method was developed to calculate the quantity of state of the closed module which is fitted with rubber buffers for the small positive pressure control system. Experiments to examine the pressure change of the closed module caused by rapid temperature control of an air conditioner were carried out at Biosphere-J. Comparison of calculated and experimental results showed that the present dynamic simulation is suited to estimating the quantity of state of the closed module.
著者
中山 満茂 荻原 五郎
出版者
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.462, pp.p725-729, 1985-02

In order to develop the low NO_x combustion system and high performance steam generator, several tests had been made. The first, to reduce NO_χ emissions , a new type swirl nozzle has been developed. The feature of this nozzle. The second, the combustion tests with package type boiler have been made. From the experimental investigations, NO_χ emission levels emitted from this combustion chamber the grooved swirl nozzle were 30-40 percent less than that of the conventional hollow-cone type swirl nozzle.
著者
高橋 陽一 末永 陽介 北野 三千雄 工藤 めぐみ
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.3046-3052, 2005
被引用文献数
2

Response of a cylindrical premixed flame to periodic concentration fluctuation was investigated. The flame was formed in a porous cylinder by percolating the mixture uniformly through the cylinder wall. The burner used here was devised so as to fluctuate the mixture concentration (equivalence ratio) only in the radial direction of the flow (vertically to the cylindrical flame surface) without varying the flow field. With this burner the time variations of burning velocity, burnt gas temperature and flame luminosity were measured for the lean methane-air mixture in the range of fluctuation frequency from 3 Hz to 50 Hz, and the results were examined from the viewpoint of flame curvature effects. The results show that the variation width of the burning velocity of the dynamic flame is larger than that of the static flame corresponding to the concentration fluctuation. Burnt gas temperature and flame luminosity also exhibit similar tendencies. The magnification ratio of the variation width depends on the flame curvature and the large flame curvature makes the flame sustainable even for the mixture leaner than the flammability limit of the static flame.
著者
藤井 照重 太田 淳一 蒋 安衆 木島 和夫 金加 貴史
出版者
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.56, no.527, pp.p2093-2097, 1990-07

In a system constructed by combining a gas turbine with a generator and an unfired waste-heat-recovery boiler,the exhausted gas becomes the heat input to the boiler and thus,the characteristics of this heat input obviously differ from those of the heat input to a conventional boiler system. To clarify the dynamic characteristics of the unfired waste-heat-recovery boiler,a simple naturalcirculation loop tube was manufactured to simulate an actual boiler. The experiments on dynamic responses with step changes in heat input were carried out for the cold start of about 10℃ and the warm start of 50℃ or 90℃. Dynamic responses such as the drum pressure,the drum water level and the natural-circulation velocity were clarified experimentally.
著者
平石 雅之 蔦原 道久
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.74, no.746, pp.2132-2137, 2008
被引用文献数
2

We propose the Spectral Lattice Boltzmann Method (SLBM) that is the numerical calculation method of fluids based on the lattice BGK (Bathnagar-Gross-Krook) model discretized with spectral method. Two-dimensional homogeneous isotropic turbulence are simulated by the SLBM. Numerical results agree with another calculation results i.e. the energy spectra proportional to the wave number to -4 and backward cascade of energy is observed. As a result, we obtain the conclusion that homogeneous isotropic turbulence can be simulated by the SLBM, and it is confirmed that this method is useful for numerical simulations of turbulent flows.
著者
稲田 英一 山下 克典 棚橋 隆彦
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 (ISSN:03875016)
巻号頁・発行日
vol.62, no.597, pp.1685-1692, 1996-05-25 (Released:2008-03-28)
参考文献数
11
被引用文献数
1 1

In the present paper, unsteady natural convection flows of air in a square cavity with differentially heated walls are investigated numerically using the hybrid-GSMAC (generalized and simplified marker and cell) finite-element method. A direct-numerical simulation of two-dimensional turbulence is shown in the present paper without introducing any random forces. The present result at Rα=1.0×108 is compared with the other numerical results. The present result of calculation is in good agreement with that of the others This study allows us to say that the hybrid-GSMAC method suggested by Tanahashi is clarified. In addition, selected frames from an animation generated from the computational results at Rα=1.0×109 show very clearly the formation of large-scale eddies via the following sequence : initial instability, proceeding through transition, and eventually the statistical steady state. Using this method, it is possible to investigate natural convection and heat transfer phenomena at high Rayleigh numbers up to 1010.
著者
新冨 雅仁 牧野 敦 藤井 淳志 荒木 信幸
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.69, no.678, pp.476-481, 2003
被引用文献数
1

An experimental study has been conducted in order to elucidate influences of additions of hydrogen and methane on the combustion synthesis of diamond films. Differences between the flat flame and the conical flame are first examined, and it is reconfirmed that the velocity gradient is one of the dominant parameters in the combustion synthesis of diamond films. Additions of hydrogen and/or methane are examined on the growth rates of diamond films, crystal sizes, and morphology. These results are also confirmed by conducting the similar experiments with a welding torch, instead of the flat flame burner. It is found that an addition of hydrogen reduces the growth rate and crystal size, while that of methane enhances those although homogeneity of the diamond films is reduced.
著者
新冨 雅仁 牧野 敦 藤井 淳志 荒木 信幸
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.68, no.675, pp.3136-3143, 2002
被引用文献数
1

An experimental study to synthesize diamond films has been conducted under a well-defined flow field to make clear the mechanism of combustion synthesis of diamond films. Using a flat flame burner, the homogeneous diamond films are synthesized on substrates, above which flat, premixed acetylene/hydrogen/oxygen flames are established. The effect of equivalence ratio and velocity gradient is examined on the growth rates of diamond films, crystal sizes, and their morphology. It is found that not only the maximum growth rate but also the maximum crystal size can be obtained when the equivalence ratio is about 2.50, and that the growth rate, crystal size, and/or morphology are nearly the same when the velocity gradient is kept constant. These results are confirmed by a conical flame with a welding torch. In addition, the scratching treatment for the substrates by diamond powder is unnecessary, the maximum growth rate of diamond films can be obtained when the surface roughness is about 0.11 μm, and the nuclei of diamond appear in scratches on the substrates.
著者
草野 茂之 段 智久 千田 二郎 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.65, no.630, pp.804-811, 1999-02-25
参考文献数
10
被引用文献数
2

In this study, new models on the new droplet evaporation taking account of the droplet surface temperature related to the modified Spalding model, on the ambient temperature and the mass fraction at the infinite-point was proposed and incorporated into KIVA-II code. These models were compared and reviewed with the droplet evaporation model of KIVA-II original code in relation to the standard Spalding model. As a results, it is found that the calculated results of droplet evaporation by new model agree well with actual phenomena.
著者
草野 茂之 段 智久 千田 二郎 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.65, no.630, pp.804-811, 1999-02-25 (Released:2008-03-28)
参考文献数
10
被引用文献数
3 4

In this study, new models on the new droplet evaporation taking account of the droplet surface temperature related to the modified Spalding model, on the ambient temperature and the mass fraction at the infinite-point was proposed and incorporated into KIVA-II code. These models were compared and reviewed with the droplet evaporation model of KIVA-II original code in relation to the standard Spalding model. As a results, it is found that the calculated results of droplet evaporation by new model agree well with actual phenomena.
著者
小垣 哲也 小林 敏雄 谷口 伸行
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.65, no.633, pp.1559-1567, 1999-05-25 (Released:2008-03-28)
参考文献数
15
被引用文献数
3 2

In order to conduct direct numerical simulation (DNS) or large eddy simulation (LES) of turbulent flows in complicated flow geometry, accurate finite difference methods are needed in generalized curvilinear coordinate system. Recently, it was shown that the analytical conservation properties of the set of basic equations are needed to be satisfied properly even in discretized basic equations in order to obtain accurate and stable solutions in simulations of incompressible turbulent flow using finite difference method. The basic equations treated here are the continuity equation, the Navier-Stokes equation and the transport equations of the square values of velocity components and the kinetic energy. In this paper, finite difference schemes in generalized curvilinear coordinate system that are suitable for simulations of incompressible turbulent flow are constructed from relatively simple extension of the proper finite difference schemes derived in equidistant Cartesian coordinate system. The extension of finite difference scheme into generalized curvilinear coordinate system is based on the fact that the analytical conservation properties of the coordinate transformed basic equations for incompressible viscous flows are identical with that in Cartesian coordinates.
著者
中島 求 面田 雄一
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.734, pp.2010-2017, 2007

The objective of this study was to develop a simulation method for analysis of body behavior in skydiving freefall and to clarify the most stable body position during the freefall. The details of the developed simulation method were firstly described. Using the simulation method, we conducted an optimizing calculation to maximize an objective function with respect to the stability in the freefall. It was found that the most stable position became arched one. In order to clarify the reason why the most stable position became arched, optimization with respect to a simple shaped object which consists of 20 cylinders was conducted. Then the angle to maximize the restoring moment for each cylinder element was analytically calculated and compared with the optimized angle. From the results, we conclude that the most stable position becomes arched mainly since the restoring moment at each part itself becomes maximum at that angle. We also conclude that the magnitude of the arch in the most stable position is determined by the ratio of the normal and tangential drag coefficients.
著者
日向 滋 桜井 正幸 姫野 修廣 岩出 浩正
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.535, pp.971-976, 1991-03-25 (Released:2008-03-28)
参考文献数
14

The theoretical study was carried out to clarify the mechanism of bubble formation through a submerged nozzle in upward water flow. On the basis of the experimental results, a model of breakup of the air column in which the surface membrane is oscillating at the top of the nozzle due to the disturbance of flow was proposed. The size of the bubble generated from a nozzle in a stream ranging from Nozzle Reynolds number 1500 to 15000 was determined by applying the theory of the instability of a jet which was first analyzed by Lord Rayleigh. The proposed model is in good agreement with the experimental results.
著者
近江 宗一 井口 学
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.47, no.418, pp.993-1001, 1981-06-25 (Released:2008-03-28)
参考文献数
26
被引用文献数
2 1

前報における円管内振動流れの速度分布や管摩擦係数に関する実験結果によれば, 振動流れの乱れ生成機構は定常流れのそれと類似している. 本報告では振動流れの乱れ生成領域は定常流れの場合と同じであるとして, 管内にこの領域が完成されたときのレイノルズ数を臨界値としてこれを評価する式を導き, 計算値が測定値とよく一致することを示すとともにバースト現象が起こる臨界周期と定常乱流の平均バースト周期との関係を求めた.
著者
小糸 康志 井村 英昭 望月 正孝 齊藤 祐士 鳥居 修一
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.72, no.714, pp.404-411, 2006-02-25 (Released:2011-03-03)
参考文献数
12
被引用文献数
1

A “Vapor Chamber” is used as a novel heat spreader to cool high-performance MPUs (micro-processor units). The vapor chamber is placed between small heat sources and a large heat sink. This paper describes the effect of heat source size on the heat transfer characteristics of the vapor chamber. First, by the experiments, the effect of heat source size on the temperature distribution of the vapor chamber is investigated, and the validity of the mathematical model of the vapor chamber is confirmed. Secondly, by the numerical analyses, the effect of heat source size on the thermal resistances inside the vapor chamber is discussed. It is found that the heat source size greatly affects the thermal resistance of the evaporator section inside the vapor chamber. Although the thermal resistance is hardly affected by the heat generation rate and the heat flux of the heat source, it increases as the heat source becomes smaller.
著者
内山 知実 成瀬 正章
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.74, no.742, pp.1324-1331, 2008-06-25 (Released:2011-03-03)
参考文献数
16

This study proposes a two-dimensional grid-free simulation method for gas-particle two-phase flow. The method is based on a vortex method, in which the vorticity field is discretized by vortex elements. The behavior of vortex element and the particle motion are simultaneously computed by the Lagrangian approach. Four square cells are allocated around each particle. In each cell, the change in the circulation of gas-phase due to the particle motion is calculated, and it is considered through the change in the strength of vortex element. The grid-free method is applied to simulate the particulate jet generated by small glass particles falling from a slit orifice into an unbounded quiescent air. It is shown that the simulated distribution of air velocity is favorably compared with the measurement. It is also confirmed that the entrained air flow rate agrees well with the prediction by an analytical model. These results suggest the validity of the method.