Details of a Researcher - Yokomori, Takeshi

Yokomori, Takeshi

写真a

Affiliation: Faculty of Science and Technology, Department of Mechanical Engineering (Yagami)

Position: Professor

Related Websites

http://www.yokomori.mech.keio.ac.jp/

External Links

Career 【 Display / hide 】

2003.10

-

2004.04

Researcher, Institute of Fluid Science, Tohoku University
2004.04

-

2007.03

JSPS Fellow(PD), Institute of Fluid Science, Tohoku University
2005.04

-

2006.03

Guest Researcher, Department of Mechanical and Aerospace Engineering, Princeton University, USA
2007.04

-

2013.03

Lecturer, Department of Mechanical Engineering, Faculty of Science and Technology, Keio University
2011.04

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2013.03

慶應義塾大学日吉2年生クラス担任

Academic Background 【 Display / hide 】

1998.03

Keio University, Faculty of Science and Technology, Department of Mechanical Engineering

University, Graduated
2000.03

Keio University, Graduate School of Science and Technology, School of Mechanical Engineering

Graduate School, Completed, Master's course
2003.09

Keio University, Graduate School of Science and Technology, School of Science for Open and Environmental Systems

Graduate School, Withdrawal after completion of doctoral course requirements, Doctoral course

Academic Degrees 【 Display / hide 】

Ph.D, Keio University, Coursework, 2004.03

Research Areas 【 Display / hide 】

Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Thermal engineering (Thermal Engineering)

Research Keywords 【 Display / hide 】

レーザー計測
Reactive thermal fluid
Flame
Combustion
Combustion synthesis

Research Themes 【 Display / hide 】

Combustion synthesis of nano-phosphor,

2005

-

Present
多孔質微粒子の燃焼合成法の開発,

2010

-

Present
コアシェル微粒子の燃焼合成法の開発,

2010

-

Present
Combustion synthesis of Carbon nanotubes,

2002

-

2009
Control of catalytic combustion,

2006

-

Present

Papers 【 Display / hide 】

Numerical study on propagation and NO reduction behavior of laminar stratified ammonia/air flames

Tomidokoro T., Yokomori T., Im H.G.

Combustion and Flame (Combustion and Flame) 241 2022.07

ISSN 00102180

　View Summary

In recently developed ammonia combustion technologies such as swirl flow and staged combustion, locally rich or lean pockets of unburned mixtures may occur due to insufficient mixing. This results in a premixed flamelet propagating into a gradually leaner or richer mixture. The present study aims to numerically investigate the propagation of laminar ammonia/air premixed flames in compositionally stratified mixtures. Results indicate that the flame speed in a rich-to-lean stratified mixture is increased from that in corresponding homogeneous mixtures at each local equivalence ratio. In contrast, the stratified flame speed is decreased in a lean-to-rich stratified mixture. The response of the stratified flame speed is attributed to variation in the amount of H2 in the burned gas. In the rich-to-lean stratified flame, an extra amount of H2 diffuses into the reaction zone to enhance chain-branching reactions which produce H radicals. The increased H radicals then promote dehydration reactions, resulting in an increased fuel consumption rate. In the lean-to-rich stratified flame, the opposite process takes place. The above mechanism is similar to the so-called back-support effect observed in methane/air stratified flames. Meanwhile, in both rich-to-lean and lean-to-rich stratified flames, additional NO reduction occurs in the stoichiometric region of the burned gas. This is facilitated by unburned ammonia diffusing from the neighboring rich burned gas mixing with O/H radicals diffusing from the neighboring lean burned gas, resulting in a production of extra NHi radicals which readily reduce NO. Therefore, NO emission in stratified flames is expected to be lower than that estimated from the emission characteristics in homogeneous mixtures. Although similar to the well-known thermal DeNOx mechanism, the current NO reduction process occurs under a much higher temperature due to the abundance of radical species. A similar phenomenon is expected to be observed in a triple flame configuration, which requires future investigations.
- Access to Document (DOI)
Experimental Investigation of the Effects of Fuel Injection on the Cycle-to-Cycle Variation of the In-Cylinder Flow in a Direct-Injection Engine Using High-Speed Particle Image Velocimetry Measurement

Kaneko Y., Nagashima T., Tomidokoro T., Matsuda M., Yokomori T.

SAE International Journal of Engines (SAE International Journal of Engines) 15 ( 6 ) 2022.02

ISSN 19463936

　View Summary

In a direct-injection (DI) engine, the in-cylinder flow is complex. Fluctuations of DI and in-cylinder flow, and the relationships between those fluctuations, are considered to affect the cycle-to-cycle variation (CCV) of combustion. However, neither the relationship between the injection conditions and the CCV of the in-cylinder flow nor the effect of the in-cylinder tumble flow on the spray has been clarified in detail. In this study, a single-cylinder optical engine was used to perform high spatial resolution particle image velocimetry (PIV) measurements and to photograph spray behavior throughout the cylinder. The spray timing was changed to investigate the timing's effects on the in-cylinder flow, the CCV, and tumble vortex center behavior. The penetration length was calculated from the spray images and compared with the PIV measurement results. The PIV results showed that the behavior of the bulk flow in the cylinder, the position of the center of the tumble vortex, and the CCV of the velocity changed depending on the presence or absence of DI and the injection timing. The overall trend was that the shorter the time elapsed after injection, the stronger the effect on the in-cylinder flow remained. The results of spray imaging revealed that the ambient flow velocity affected the direct spray at the time of injection when the flow velocity was high in the spray direction and that the spray extended faster. In addition to the advantage of the longer diffusion time, the fast in-cylinder flow in the same direction as the direct jet did not cause much momentum exchange with the spray, while making it easier for the spray to diffuse throughout.
- Access to Document (DOI)
Flame Aerosol Synthesis of Core-Shell Particles

YOKOMORI Takeshi, TOMIDOKORO Takuya

Journal of the Combustion Society of Japan (Combustion Society of Japan) 63 ( 205 ) 201 - 209 2021

ISSN 1347-1864

　View Summary

<p>Core shell particles comprise a core content and a coating shell of another material. The core shell structure can realize a new functional material that cannot be realized by a particle which has only a single composition. Wet chemical synthesis is commonly used in the fabrication of core–shell particles, but recently, some reports on flame aerosol synthesis of core-shell particles have been published. Flame aerosol synthesis can offer continuous one-step production process including high-temperature treatment, and results in high-purity fine crystalline particles. Therefore, it is expected that flame aerosol synthesis method for core-shell particles will be further developed in the future. In this paper, we explain the details of flame aerosol synthesis method for core-shell particles and give an interpretation of the physical processes.</p>
- Access to Document (DOI)
- CiNii Research
Lifetime characteristics of co-doped phosphor and performance improvement of thermometry by simultaneous measurement on two wavelengths

MATSUSHITA Yuki, YOKOMORI Takeshi

The Proceedings of Conference of Kanto Branch (The Japan Society of Mechanical Engineers) 2021 ( 0 ) 10A15 2021

　View Summary

<p>The effects of co-doping in phosphors and the use of co-doped phosphors to extend the temperature measurement range were experimentally investigated in terms of the lifetime method. Such effects can be evaluated by comparing the single and double luminescent centers. In this study, YAG:Tb, YAG:Cr and YAG:Cr,Tb were prepared by sol-gel method and the luminescence intensity was measured under excitation by the 4<sup>th</sup> harmonic of Nd:YAG laser. In order to improve the temperature measurement performance of YAG:Cr,Tb, it is desirable to divide it into two wavelength regions with a threshold around 600 nm, and to switch between the two regions depending on the temperature range when performing temperature measurement by the lifetime method. The absolute lifetime sensitivity <i>S<sub>A</sub></i> is a suitable index to use when dividing the temperature region into two regions, resulting in switching at around 800 K. The lifetime of the Cr-derived luminescence is slightly longer, while that of the Tb-derived luminescence is about 10 times shorter.</p>
- Access to Document (DOI)
- CiNii Research
Improved knock detection method for lean burn SI engines

OKADA Rikiya, YASUTAKE Yuki, MIYOKAWA Shinji, TOMIDOKORO Takuya, YOKOMORI Takeshi

The Proceedings of Conference of Kanto Branch (The Japan Society of Mechanical Engineers) 2021 ( 0 ) 10A16 2021

　View Summary

<p>The purpose of this study was to improve the accuracy of knock detection for lean burn SI engines. In this study, we conducted an experiment to observe autoignition in an engine cylinder using a borescope and a high-speed camera under an air excess ratio of 2.1. In addition, the resonance frequency of each vibration mode by knocking and the knock intensity were also calculated from the in-cylinder pressure history. Autoignition was optically observed in all cycles with a knock intensity of more than 20 kPa or more, and in some cycles with that of less than 20 kPa. We compared the vibration caused by combustion and it caused by autoignition. As a result, by distinguishing between the vibration caused by combustion and it caused by autoignition using window functions, a knocking cycle that could not be detected by the conventional index was detected.</p>
- Access to Document (DOI)
- CiNii Research

Papers, etc., Registered in KOARA 【 Display / hide 】

Novel synthesis method of core shell oxide particles by flame spray pyrolysis

Yokomori, Takeshi

科学研究費補助金研究成果報告書 2016
コツコツが必要で大事

Yokomori, Takeshi

新版窮理図解 (慶應義塾大学理工学部) ( 18 ) 2014.11
Work assiduously : this is the key to success

Yokomori, Takeshi

New Kyurizukai (Faculty of Science and Technology, Keio University) ( 18 ) 2014.11
Two-dimensional simultaneous temperature and velocity measurements using co-doped phosphor particles

Yokomori, Takeshi

科学研究費補助金研究成果報告書 2012
Size-controlled nanophosphors prepared by gas-phase flame synthesis with vapor precursors

Yokomori, Takeshi

科学研究費補助金研究成果報告書 2009

Reviews, Commentaries, etc. 【 Display / hide 】

Fundamentals and Principles of Phosphor Thermometry

YOKOMORI Takeshi, ISHIWADA Naohiro

Journal of the Combustion Society of Japan (Combustion Society of Japan) 62 ( 201 ) 234 - 241 2020.08

Article, review, commentary, editorial, etc. (scientific journal), Joint Work, ISSN 1347-1864

　View Summary

Accurate and reliable temperature measurements are crucial to improve the thermal efficiency and optimize the design of products because temperature is an important parameter to understand heat conduction, convention, radiation, and chemical reactions. The emission properties of phosphors are sensitive to temperature, hence, phosphor thermometry can make remote temperature sensing. Accordingly, phosphor thermometry has received considerable attention as a versatile alternative to conventional temperature measurement techniques. This article describes the principles and fundamental aspects of phosphor thermometry, that is, principles of luminescence, temperature dependences of luminescence characteristics and how to use those dependence characteristics such as life time method and spectral intensity ratio method.
- Access to Document (DOI)
Non-contact temperature measurement by two-color phosphor thermometry

Takeshi YOKOMORI, Naohiro ISHIWADA

Heat Transfer (日本伝熱学会) 58 ( 245 ) 15 - 20 2019.10

Article, review, commentary, editorial, etc. (scientific journal), Joint Work
A high speed PIV measurement on the in-cylinder flow in an SI IC engine

Masayoshi Matsuda, Takeshi Yokomori

Image Laboratory 30 ( 9 ) 45 - 51 2019.09

Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Joint Work
Research and Development on Super Lean Burn Combustion for High Efficiency SI Engines

飯田訓正, 横森剛, 津江光洋, 北川敏明, 小酒英範, 三好明, 森吉泰生

日本燃焼学会誌 (日本燃焼学会) 61 ( 197 ) 178 - 192 2019

Article, review, commentary, editorial, etc. (scientific journal)
- Access to Document (DOI)
PIVを用いたエンジン筒内の流動計測技術

横森剛, 松田昌祥

計測と制御 57 ( 5 ) 313 - 317 2018.05

Article, review, commentary, editorial, etc. (scientific journal)

Presentations 【 Display / hide 】

Effect of Surfactant on the Methane Hydrate Combustion

K. Mizuochi, T. Yokomori, R. Ohmura, T. Ueda

37th International Symposium on Combustion (Dublin, Ireland) ,

2018.07
,
Poster presentation, The Combustion Institute

　View Summary

4P229
Criterion of the Transition from Quasi-Steady State to Non-Steady State Motion of Laminar Stagnating Premixed Flames with Fuel Concentration Oscillation

T. Ueda, D. Kawasaki, K. Kashiwagi, T. Yokomori

37th International Symposium on Combustion (Dublin, Ireland) ,

2018.07
,
Poster presentation, The Combustion Institute

　View Summary

1P090
Numerical Simulation of Soot Particle Growth Including Sintering

T. Kim, K. Takigawa, T. Yokomori

37th International Symposium on Combustion (Dublin, Ireland) ,

2018.07
,
Poster presentation, The Combustion Institute

　View Summary

2P045
Numerical Simulation of the Structure Growth of Silica Nanoparticles with a Conditional Quadrature Method of Moments Considering Fractal Dimension

K. Takigawa, T. Yokomori

37th International Symposium on Combustion (Dublin, Ireland) ,

2018.07
,
Poster presentation, The Combustion Institute

　View Summary

2P049
Effect of Simultaneous Velocity and Equivalence Ratio Oscillations on the Laminar Premixed Stagnating Flame

Y. Niwa, T. Tomidokoro, T. Yokomori, T. Ueda

37th International Symposium on Combustion (Dublin, Ireland) ,

2018.07
,
Poster presentation, The Combustion Institute

　View Summary

2P072

Research Projects of Competitive Funds, etc. 【 Display / hide 】

Elucidation of unstable combustion and construction of its AI-based sign detection for hydrogen combustion under lean-burn condition

2022.04

-

2025.03

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), No Setting

　View Summary

近年，化石エネルギーからカーボンフリーエネルギーへの大転換が避けられない喫緊の課題となっている．水素は，その燃焼過程において二酸化炭素を全く排出しない究極のカーボンフリー燃料として，様々な燃焼装置への利用が期待されている．しかし，水素の希薄燃焼は，装置損傷の原因となる不安定燃焼を引き起こすリスクがある．そこで，本研究では，不安定燃焼として特に問題視されている燃焼振動とフラッシュバックに着目し，精巧な実験と高精度の数値解析により，これらの発生メカニズムと詳細特性を明らかにする．また，不安定燃焼の事前察知・抑制を目指し，不安定燃焼が発生する予兆の検知をAIとの連携により実現する技術を構築する．
Elucidation of mechanism of combustion noise generation and modulation from turbulent lean premixed swirling flame

2019.04

-

2022.03

Kyoto University, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), No Setting

　View Summary

航空機用や産業用に用いられるガスタービンエンジンから発生する騒音は，ファンや排気ジェットを音源とする流体騒音と燃料/酸化剤の発熱反応を音源とする燃焼騒音とに大別される．近年，流体騒音の低減が着実に進んでいる一方で，燃焼騒音の寄与率が急激に上昇し，その低減が喫緊の課題とされている．しかし，燃焼騒音については，その発生メカニズムすら十分に理解されていない．また，燃焼騒音は壁反射や乱流渦等の外的因子により変調するが，その影響についてはこれまで議論されていない．本研究では，水素の乱流希薄予混合旋回火炎を対象に実験と数値解析を併用することより，燃焼騒音の発生・変調メカニズムを明らかにすることを目指す．
平成27年度火炎伝播方向が高分子材料内部の温度分布に与える影響評価

2015.09

-

2016.03

国立研究開発法人宇宙航空研究開発機構（JAXA）, Commissioned ｒesearch, Principal investigator
高効率ガソリンエンジンのためのスーパーリーンバーン研究開発

2014.10

-

2019.03

独立行政法人科学技術振興機構, 戦略的イノベーション創造プログラム（SIP）「革新的燃焼技術」, Research grant, Coinvestigator(s)
平成26年度「火災安全性向上に向けた固体材料の燃焼現象に対する重力影響の評価」に関わる宇宙実験のデータ解析等（特に固体内部温度の計測）

2014.08

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2015.03

国立大学法人豊橋技術科学大学, Joint research, Principal investigator

Intellectual Property Rights, etc. 【 Display / hide 】

点火プラグ

Date applied： 2018-023533 2017.12

Patent, Joint
燃焼制御方法

Date applied：特願2016-163095 2016.08

Date announced：特開2018-31500 2018.03

Patent, Joint
燃焼制御方法

Date applied：特願2016-162824 2016.08

Date announced：特開2018-31499 2018.03

Patent, Joint
温度及び酸素濃度測定装置

Date applied：特願2014-019213 2014.02

Date announced：特開2015-145852 2015.08

Date issued：特許6264912号 2018.01

Patent, Joint
加熱調理器の制御装置

Date applied：特願2011-209681 2011.09

Date announced：特開2013-72562 2013.04

Patent, Joint

Awards 【 Display / hide 】

日本機械学会熱工学部門一般表彰貢献表彰

2016.10, 日本機械学会

Type of Award： Award from Japanese society, conference, symposium, etc.
日本機械学会関東支部関東学生会第55回学生員卒業研究発表会優秀講演賞

松田昌祥, 藤澤直己, 横森剛, 2016.03, 日本機械学会, 高速PIV 計測および数値計算を用いたガソリンエンジンにおける筒内流動解析

Type of Award： Award from Japanese society, conference, symposium, etc.
日本機械学会若手優秀講演フェロー賞

篠直希, 2015.11, 日本機械学会, 蛍光粒子を利用したガス流二次元温度・速度同時測定法の開発

Type of Award： Award from Japanese society, conference, symposium, etc.
日本機械学会関東支部関東学生会第54回学生員卒業研究発表会優秀講演賞

小川裕太, 楠拓朗, 横森剛, 2015.03, 日本機械学会, 二段火炎を導入したコアシェル粒子噴霧燃焼合成法の開発

Type of Award： Award from Japanese society, conference, symposium, etc.
日本機械学会関東支部関東学生会第54回学生員卒業研究発表会優秀講演賞

荻真太郎, 岡野紗耶, 横森剛, 2015.03, 日本機械学会, 燐光体の発光特性を利用した温度・酸素濃度同時測定手法の開発

Type of Award： Award from Japanese society, conference, symposium, etc.

Courses Taught 【 Display / hide 】

LABORATORIES IN SCIENCE AND TECHNOLOGY

2024
INDEPENDENT STUDY ON SCIENCE FOR OPEN AND ENVIRONMENTAL SYSTEMS

2024
GRADUATE RESEARCH ON SCIENCE FOR OPEN AND ENVIRONMENTAL SYSTEMS 2

2024
GRADUATE RESEARCH ON SCIENCE FOR OPEN AND ENVIRONMENTAL SYSTEMS 1

2024
FACTORY VISITING

2024

Social Activities 【 Display / hide 】

日本燃焼学会平成25年度先進的燃焼技術の調査研究委員会新概念燃焼技術小委員会

2013.12

-

2014.03
日本伝熱学会

2013.06

-

Present
日本燃焼学会震災後の社会・エネルギー情勢に必要とされる燃焼利用技術の調査研究分科会

2013.04

-

Present
日本機械学会熱工学部門

2013.04

-

Present
日本機械学会熱工学部門総務委員会

2013.04

-

Present

Memberships in Academic Societies 【 Display / hide 】

ゼロエミッションモビリティパワーソース研究コンソーシアム,

2020.04

-

Present
自動車技術会,

2016.01

-

Present
日本液体微粒化学会,

2015.01

-

Present
日本機械学会,

2006.06

-

Present
American Institute of Aeronautics and Astronautics,

2006.01

-

2008.12

Committee Experiences 【 Display / hide 】

2015.04

-

2016.03

Japanese Scientific Committee, The First Pacific Rim Thermal Engineering Conference
2014.04

-

Present

委員, 文部科学省科学技術政策研究所科学技術動向研究センター
2014.04

-

Present

委員, 日本機械学会熱工学部門運営委員会
2014.04

-

Present

委員, 日本機械学会熱工学部門部門賞委員会
2014.04

-

Present

幹事, 日本機械学会熱工学部門総務委員会