研究者詳細 - 河原　伸幸

MISC - 河原　伸幸

分割表示 242 件中 1 - 20 件目／全件表示 >>

第29回内燃機関シンポジウム（8.ガソリン噴霧）

河原伸幸

自動車技術会，Engine Review 9 ( 4 ) 2019年8月

８.ガソリン噴霧

河原　伸幸

Engine Review 9 ( 4 ) 32 - 33 2019年7月

光学的燃焼可視化装置による燃料噴射ノズル内部の旋回流が燃焼特性に及ぼす影響の調査

山下裕雅, 河原伸幸, 坪井和也, 冨田栄二, 藤井幹, 森中和宏

マリンエンジニアリング学術講演会講演論文集 89th 2019年

新しい計測診断技術（エンジン計測技術）

河原　伸幸

Engine Review 8 ( 3 ) 17 - 19 2018年5月

エンジン筒内の燃料濃度計測技術

河原伸幸

計測自動制御学会，「計測と制御」５月号 57 328 - 332 2018年5月

新しい計測診断技術（エンジン計測技術）

河原伸幸

自動車技術会，Engine Review 8 ( 3 ) 17 - 19 2018年5月

エンジン筒内の燃料濃度計測技術

河原　伸幸

計測と制御 57 328 - 332 2018年5月

光学的燃焼可視化装置(OCA)による極低硫黄燃料油の着火性および燃焼性の評価

窪田裕也, 冨田栄二, 河原伸幸, 坪井和也, 宮地健, 近藤守男

マリンエンジニアリング学術講演会講演論文集 88th 2018年

Visualization of combustion processes of internal combustion engines

Nobuyuki Kawahara

The Micro-World Observed by Ultra High-Speed Cameras: We See What You Don't See 261 - 275 2017年8月

記述言語：英語出版者・発行元：Springer International Publishing

Very fast visualization of fuel injection and spray impingement on the wall, the laser ignition process, and auto-ignition of the end-gas region due to flame propagation during the engine knock cycle was demonstrated using an ultra-high-speed camera for a detailed understanding of the combustion process inside an internal combustion (IC) engine. The combustion process of an IC engine is complex, involving several thermal fluid phenomena. The high-speed video camera was an essential tool for visualizing and recording these high-speed phenomena. When more magnified images are needed, the ultra-high-speed camera and a long-distance microscope with a Barlow lens were used. Here, high-speed visualization techniques were shown to understand the combustion process inside an IC engine.

DOI： 10.1007/978-3-319-61491-5_12

Scopus

researchmap

Multidimensional CFD simulation of diesel spray combustion using chemical kinetics

Nobuyuki Kawahara, Norihiro Takeda, Eiji Tomita

COMODIA 2017 - 9th International Conference on Modeling and Diagnostics for Advanved Engine Systems 2017年1月

Copyright © 2017 by the Japan Society of Mechanical Engineers. The purpose of this study is to simulate the process from spray injection to spray combustion in a rapid compression machine (RCM) more precisely. Spray behavior and spray combustion were simulated by Generalized Tank and Tube (GTT) code which is based on KIVA code. First, the model coefficients of modified wave break-up model for liquid droplet break-up were considered using experimental results of droplet diameter and velocity obtained using a laser 2-focus velocimeter (L2F). Calculation results of spray tip penetration under atmospheric conditions were good agreement with experimental from the visualization of isothermal spray under higher injection pressure conditions. Second, multidimensional CFD simulations of diesel spray combustion using the reduced chemical kinetics were carried out under RCM experimental conditions with 900 K of ambient temperature and 4.1 MPa of ambient pressure. The modelled results were validated by comparing predictions against corresponding experimental results in RCM. The predicted and measured in-cylinder pressure were in good agreement. Ignition process of diesel spray combustion of free spray in RCM were discussed with spray break-up phenomena, entrainment structure of higher injection pressure, and OH radical formation of diesel spray combustion.

DOI： 10.1299/jmsesdm.2017.9.B103

Scopus

researchmap

Chemical Kinetics and Computational Fluid-Dynamics Analysis of H2/CO/CO2/CH4 Syngas Combustion and NOx Formation in a Micro-Pilot-Ignited Supercharged Dual Fuel Engine

Nearchos Stylianidis, Ulugbek Azimov, Nobuyuki Kawahara, Eiji Tomita

SAE Technical Papers 2017- 394 - 404 2017年

記述言語：英語出版者・発行元：SAE International

A chemical kinetics and computational fluid-dynamics (CFD) analysis was performed to evaluate the combustion of syngas derived from biomass and coke-oven solid feedstock in a micro-pilot ignited supercharged dual-fuel engine under lean conditions. For this analysis, a reduced syngas chemical kinetics mechanism was constructed and validated by comparing the ignition delay and laminar flame speed data with those obtained from experiments and other detail chemical kinetics mechanisms available in the literature. The reaction sensitivity analysis was conducted for ignition delay at elevated pressures in order to identify important chemical reactions that govern the combustion process. We have confirmed the statements of other authors that HO2+OH=H2O+O2, H2O2+M=OH+OH+M and H2O2+H=H2+HO2 reactions showed very high sensitivity during high-pressure ignition delay times and had considerable uncertainty. The chemical kinetics of NOx formation was analyzed for H2/CO/CO2/CH4 syngas mixtures by using counter flow burner and premixed laminar flame speed reactor. The new mechanism showed a very good agreement with experimental measurements and accurately reproduced the effect of pressure, temperature and equivalence ratio on NOx formation. In order to identify the species important for NOx formation, a sensitivity analysis was conducted for pressures 4 bar, 10 bar and 16 bar and preheat temperature 300 K. The results show that the NOx formation is driven mostly by hydrogen based species while other species, such as N2, CO2 and CH4, have also important effects on combustion. Finally, the new mechanism was used in a multidimensional CFD simulation to predict the combustion of syngas in a micro-pilot-ignited supercharged dual-fuel engine and results were compared with experiments. The mechanism showed the closest prediction of the in-cylinder pressure and the rate of heat release (ROHR).

DOI： 10.4271/2017-24-0027

Scopus

researchmap

第27回内燃機関シンポジウム（点火）

自動車技術会，Engine Review 7 ( 6 ) 17 - 18 2017年

新しい計測診断技術Ⅲ（新しい流れ計測技術）

自動車技術会，Engine Review 7 ( 1 ) 14 - 15 2017年

Evaluation of Nozzle Exit Model for Transient Spray in a Multi -Hole DISI Injector

Nobuyuki Kawahara, Shuhei Takada, Eiji Tomita

19th Annual Conference of ILASS-Asia 2017年

DISIエンジンにおける燃料噴霧の壁面衝突挙動 : 表面粗さが臨界Weber数に与える影響

河原伸幸, 金高享平, 冨田栄二

微粒化シンポジウム講演論文集 25 177 - 183 2016年12月

ディーゼル噴霧燃焼の数値解析における初期条件の検討

河原伸幸, 武田規弘, 冨田栄二

微粒化シンポジウム講演論文集 25 206 - 212 2016年12月

DISIエンジンにおける燃料噴霧の壁面衝突挙動 : ノズル出口モデルおよび壁面衝突挙動の数値計算による検証

河原伸幸, 高田修坪, 冨田栄二

微粒化シンポジウム講演論文集 25 171 - 176 2016年12月

熱効率向上を指向した噴射時期と噴流形状による高圧筒内直接噴射水素エンジンの熱効率向上に関する研究

高木靖雄, 森裕樹, 中川研司, 三原雄司, 冨田栄二, 河原伸幸

自動車技術会論文集 47 ( 3 ) 705 - 710 2016年5月

DISI用インジェクタにおけるノズル出口モデルの構築

河原伸幸, 外村圭司, 冨田栄二

微粒化シンポジウム講演論文集 24 103 - 108 2015年12月

Effect of Bio-Gas Contents on SI Combustion for a Co-Generation Engine

Yungjin Kim, Nobuyuki Kawahara, Eiji Tomita, Hiroshi Oshibe, Koichi Nishikawa

SAE Technical Papers 2015- ( September ) 2015年9月

記述言語：英語出版者・発行元：SAE International

Bio-gas as an internal combustion (I.C.) engine fuel has many advantages such as cheaper fuel cost, low emission levels and especially the neutral recirculation loop of carbon dioxide, which is one of the principal factors in global warming. In this study, positive potentialities of bio-gas were investigated using a micro co-generation engine. The mixing ratio of methane (CH4) and carbon dioxide (CO2) was changed to simulate various types of bio-gases. Intake air and fuel flow rates were controlled to change the equivalence ratio. The engine load condition could be changed with the electric output power used. Base on the result, the higher CO2 content rate slowed down the engine speed in the same load condition and the combustion speed generally decreased under the same load condition with maintaining the engine speed. However thermal efficiency increased with lean burn conditions and NOX emission decreased with higher CO2 mixing rates.

DOI： 10.4271/2015-01-1946

Scopus

researchmap

　前のページ - 次のページ　

<河原 伸幸>

MISC - 河原 伸幸

<河原　伸幸>

MISC - 河原　伸幸