著者

金子 成彦 渡邉 辰郎 北澤 進

出版者

公益社団法人日本ガスタービン学会

雑誌

日本ガスタービン学会誌 (ISSN:03874168)

巻号頁・発行日

vol.30, no.4, pp.283-287, 2002-07-20

被引用文献数

5

著者

山崎 由大 金子 成彦

出版者

一般社団法人 日本燃焼学会

雑誌

日本燃焼学会誌 (ISSN:13471864)

巻号頁・発行日

vol.49, no.150, pp.236-245, 2007 (Released:2018-03-20)

参考文献数

7

被引用文献数

2

著者

新木 悠斗 上道 茜 山﨑 由大 金子 成彦

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.861, pp.17-00507-17-00507, 2018 (Released:2018-05-25)

参考文献数

8

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As a method for mining offshore gas fields, a floating production, storage and offloading (FPSO) system is attracting attention. However, sloshing in the oil-gas separator installed in FPSOs excited by sea waves is expected to cause significant difficulties. To suppress sloshing wave heights, one possibility may be to install perforated plates in a tank. In this study, a method is proposed for the accurate estimation of the first resonant wave height in the horizontal cylindrical tank with a perforated plate under pitching excitation in less time. To accomplish this purpose, the pressure loss due to the perforated plate in the open channel must be estimated accurately. Therefore, the pressure loss is modeled using steady CFD calculations considering the effects of the distribution of the flow velocity and the distribution of the inflow angle. The first order sloshing wave height is calculated in the theoretical analysis by substituting the pressure loss calculated in steady CFD. The wave heights determined using the pressure loss utilized by steady CFD are compared with the experimental value measured with a small-scale model. Using the method proposed in this study, the first resonant wave height of sloshing wave height is calculated accurately in less time.

著者

金子 成彦 宮野 芳寛 北澤 進 渡邉 辰郎

出版者

一般社団法人 日本機械学会

雑誌

動力・エネルギー技術の最前線講演論文集 : シンポジウム 2004.9 (ISSN:24242950)

巻号頁・発行日

pp.59-64, 2004-06-22 (Released:2017-06-19)

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Generators with small gas turbines that generate less than 100kW are drawing attention as a power source of cogeneration systems. Dynamic pressure type air foil bearings are expected to serve as shaft bearings. The design that these bearing are simply designed, easy to produce and maintenance free without requiring lubrication, holds the key to miniaturization of micro-gas turbines. However, the details of such design guidelines have not been clarified though this technology is used in APC for aircraft units. In this study, in order to obtain design guidelines of foil bearing, in making the foil to be the discretion beam, the modeling of the foil was carried out. Taking the frictional forces of attachment part of the foil and the protrusion, etc. into consideration, static characteristic and dynamic characteristic were analyzed to examine performance and stability of the radial foil bearing.

著者

角谷 健斗 進藤 友陽 金子 成彦

出版者

一般社団法人 日本機械学会

雑誌

Dynamics & Design Conference

巻号頁・発行日

vol.2018, 2018

被引用文献数

1

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<p>These days, the number of traffic accidents due to drivers' sudden diseases is increasing. Therefore, it is desired to detect sudden diseases by making use of drivers' biological signals measured while driving. To detect such diseases, we need to know how biological signals change with the disorders. However, it is difficult to measure physiological signals at sudden diseases and propose the method for detecting such conditions. In this study, we construct a cardiovascular model which can reproduce mechanism of a cardiovascular system, and calculate biological signals by assuming sudden diseases in the model. In the cardiovascular model, stroke volume, the blood volume pumped by a heart per beat, is determined based on the operating conditions of the system. Besides, we considered positions of baroreceptors and pressure sensors of a cardiac system in blood vessels. Then, we succeed to construct detection method for sudden diseases based on the calculated biological signals. We use K-nearest method and LOF method for a detection algorithm and found that combination of systolic blood pressure and heartbeat interval is adequate for detection, and LOF method is useful for the discrimination of disease.</p>

著者

清水 豊禾 金子 成彦 草鹿 仁

出版者

一般社団法人 日本機械学会

雑誌

年次大会

巻号頁・発行日

vol.2019, 2019

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<p>Recently, traffic accidents due to the sudden change in the physical condition of the driver is attracting attention. In our previous study, we constructed a cardiovascular model capable of reproducing the mechanism of a cardiovascular system, and calculated biological signals by assuming sudden diseases in the model. In the cardiovascular model, stroke volume, the blood volume pumped by a heart per beat, is determined based on the operating conditions of the system considering the positions of baroreceptors and pressure sensors of a cardiac system in blood vessels. However, the simulated result did not well reproduce the measured pulse wave signal. In this study, we reexamined the treatment of bifurcation part of the blood vessel and successfully improved the accuracy of the simulation.</p>

著者

上道 茜 金築 一平 金子 成彦

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.861, pp.17-00514-17-00514, 2018 (Released:2018-05-25)

参考文献数

15

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Hydrogen combustion is attracting attentions because of zero CO2 emission. Recently, a gas turbine which uses hydrogen-rich fuel is being developed. In our previous study, we examined the influence of hydrogen-containing ratio on combustion oscillation for fuel mixtures of hydrogen and town gas (13A) experimentally. In the experiment, pressure oscillations were measured by a sensor which is installed at the bottom of the combustor. It is found that two oscillation frequencies near 200 Hz and 400 Hz were simultaneously detected in the case of hydrogen-containing fuels, whereas single oscillation frequency around 350 Hz was observed in the case of only 13A fuel. To understand this difference of oscillating frequencies, we conducted acoustic analysis using one-dimensional different diameter acoustic model. However, this simplest model could not reproduce three types of oscillating frequencies obtained by the experiment. Besides, we used an acoustic impedance of the bottom of the combustion chamber as an acoustic boundary condition. The acoustic impedance is measured experimentally under the noncombustion (cold) condition and corrected by combustion temperature obtained by equilibrium calculation. As a result of applying the corrected acoustic impedance, the three types of oscillating frequencies could be reproduced by acoustic analysis. Furthermore, to express the difference among fuel mixtures, delay times, flame positions, and the mean temperature in the chamber were calculated by the CFD simulation. Consequently, it is found that the acoustic analysis result could reproduced the difference among fuel mixtures; hydrogen makes the oscillating frequencies a little higher, because temperature becomes higher and delay time becomes shorter.

著者

上杉 康登 山崎 由大 金子 成彦 疋田 孝幸 津村 雄一郎 水野 沙織

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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00537-16-00537, 2017 (Released:2017-06-25)

参考文献数

15

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To predict the combustion characteristic of auto ignition combustion in internal combustion engines, it is necessary to consider the inhomogeneity of the fuel, EGR and air in the mixture. In this research, a PDF (Probability Density Function) combustion model considering the influence of the inhomogeneity of mixture on the auto ignition combustion is developed. In our approach, the PDF of the injected fuel and the EGR gas is predicted by two-zone turbulent mixing model and only the PDF at the top dead center of the combustion stroke is used to calculate combustion characteristic to realize the reasonable calculation time for the control system design tool. The prediction model was validated by comparing with the experimental result for various injection timings and EGR ratios. It found that the model can qualitatively predict the combustion characteristics with reasonable calculation time.

著者

金子 成彦

出版者

一般社団法人日本機械学会

雑誌

日本機械学會誌 (ISSN:00214728)

巻号頁・発行日

vol.116, no.1130, pp.1-2, 2013-01-05

著者

延廣 良香 向井 美紀 小倉 由美 藤田 悦則 村田 幸治 亀井 勉 辻 敏夫 金子 成彦 吉栖 正生

出版者

一般社団法人 日本機械学会

雑誌

Dynamics & Design Conference

巻号頁・発行日

vol.2011, pp._207-1_-_207-10_, 2011

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For the homeostatic control, there are Ultra Low Frequency (ULF) fluctuations on the backbone of the control. We think we can extrapolate state of human by capturing variation of ULF fluctuations. In this study, a method was conceived for capturing ULF fluctuations by performing the time series of the gradients analysis of the pulse wave taken from the surface of the back, which was defined as an aortic pulse wave (APW) with zero-cross detection method or peak detection method. APW was recorded during an experiment with an induced sleep test in the sitting position. The results indicated that we can find drowsiness, a predictive signal for falling asleep and an impending sleep by catching variability of 0.0017Hz, 0.0035Hz and 0.0053Hz of ULF fluctuations of APW obtained by the analytical method we had invented.

著者

金子 成彦 斎藤 登 渡邉 辰郎

出版者

東京大学

雑誌

基盤研究(B)

巻号頁・発行日

2000

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本研究は、高速増殖炉「もんじゅ」のナトリウム漏洩事故で発生した、温度計ウェルの流れ方向振動に起因する温度計さや管の自励振動に関係するものである。動燃事業団(現:核燃料サイクル事業団)から提出された報告書によると、特定の一本の温度計ウェルが損傷した理由は、損傷した温度計ウェル内の熱電対が曲がって挿入されたため熱電対鞘管の内壁に接触し、温度計ウェルは1自由度系として振る舞い、大きな振動が発生し疲労破壊に至ったとのことである。この事実は、損傷を受けなかった他の温度計ウェルでは、熱電対が熱電対鞘管の内壁に常時接触してはいないので、振動することが可能で、熱電対は副振動系の役目を果たし、ダイナミックダンパを構成し、熱電対鞘管の振動を抑制したため破損しなかったことを示唆している。このように対称渦によって発生する流体振動現象は、複雑で、完全には解明できていない現象である。そこで本研究では、電力中央研究所我孫子研究所にある重力落下式水槽を用いて、加振円柱に作用する対象渦の放出による変動流体力の詳細な測定を行い、その結果を、定常流体力、加振変位に比例する変動流体力、加振変位と90度位相のずれた変動流体力に分けて、換算流速(無次元流速)と加振振幅の非線形関数で表現したデータベースを構築した。その結果を元に、振幅がある一定の大きさになった時に始めて発振が起こる硬発振の振動系であることを明らかにした。これまでにデータの蓄積ない、微小振幅の条件下での流体力の測定に初めて成功し、流れ方向の抗力は、対称渦が発生しているときには、その大きさが約二分の一に減少するという事実が判明した。

著者

菅野 雅信 赤石 誉幸 山崎 由大 金子 成彦

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.76, no.763, pp.403-405, 2010-03-25

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To realize stable operation of microgrids, gas engines require to compensate load changes from demands and variation of other renewable energy devices. Then, prehension of load following capability is important in gas engines. In addition, when biomass gas is supplied to gas engines, effect of fuel component variation on dynamic characteristics must be investigated, because components of biomass gas depend on operating condition of gasification or raw material. This study proposed a dynamic simulation model of gas engine and estimated transient response to load changes. Load changes were sinusoidal wave, and bias value, amplitude and frequency of them were varied. As a result, the frequency has more influence on transient response than the bias value and the amplitude. When biomass gas is supplied to gas engines, transient response is worce than city gas over the frequency of 0.1Hz.

著者

金子 成彦

出版者

東京大学

雑誌

挑戦的萌芽研究

巻号頁・発行日

2008

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入眠予兆信号とは、人間が眠りに入る少し手前で観察される前兆信号のことで、本研究では、これまで行なってきた入眠予兆現象の研究内容を掘り下げて学理に繋げるための研究を行った。本研究は、センサーの精度に関係する、設計条件、使用条件、外乱要因の把握による設計方法の提案を目的とする部分と、カオス解析、ウェーブレット解析、ケプストラム解析の3つの手法による入眠予兆信号の抽出方法と発生時期の相互比較、および、入眠予兆現象の原理と測定原理を表すことが可能な数学モデルの提案の3つのパートによって構成される。平成20年度は、エアパックセンサーの精度に関する検討、平成21年度は、解析手法間の相関に関する検討、平成22年度は、測定原理を表すことが可能な数学モデルの検討と入眠予兆現象捕捉のための新たな手法の提案を行った。平成22年度の研究成果は、以下の通りである。本研究では、脈波の揺らぎから入眠予兆信号を取得している。ドライバーの邪魔にならない場所で非侵襲で脈波の情報を取得するために、運転席シートの背部に取り付けた空気圧の変化を利用したセンサーを使用している。本年度は、測定原理を明らかにする目的で、脈波伝達経路を表現することのできる伝達関数を求めことに成功した。心臓の拍動が背部大動脈血管伝わる仕組みについて解析可能な動脈網モデルによる脈波伝播シミュレーションを行い、血管内の圧力が筋肉、皮膚、衣服を経由してセンサーに到達するまでの経路について解明することができた。また、昨年度の研究で見つけた新たな処理方法である、「ヒトの眠気をスリープスコアという点数で表現する」方法を被験者数を増やして実施し、成果を論文発表した。