研究者業績
基本情報
- 所属
- 国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 宇宙飛翔工学研究系 教授総合研究大学院大学 先端学術院 宇宙科学コース 教授
- 学位
- 博士（工学）(1995年3月 東京大学)
- J-GLOBAL ID
- 200901056190267532
- researchmap会員ID
- 1000253787
- 外部リンク
研究キーワード
5研究分野
3主要な経歴
15-
2019年 - 現在
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2020年 - 2024年6月
学歴
2-
- 1995年
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- 1990年
委員歴
6-
2020年 - 2023年3月
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2014年 - 2022年3月
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2014年 - 2015年
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2014年 - 2015年
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2011年 - 2015年
受賞
3-
2014年
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2012年
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1999年
論文
290-
Journal of Propulsion and Power 1-10 2024年6月20日A coupled cylindrical rotating detonation engine (RDE) with two cylindrical RDEs (both combustors had a combustor inner diameter of 23 mm and an axial length of 30 mm) placed next to each other was tested for rocket clustering application. The objective of the experiment was to achieve two-engine synchronized initiation with a single igniter. Experiments were conducted on the inner wall of the combustors with different connecting-hole diameters and wall heights to evaluate the ignition delay time, combustion mode, and propulsion performance. The propellants were gaseous ethylene and oxygen, and experiments were conducted under constant conditions of mass flow rate ([Formula: see text]), equivalence ratio ([Formula: see text]), and backpressure (approximately 10 kPa). When the two combustion chambers were completely separated by a wall, ignition occurred with a time delay of 260 ms in the chamber without an igniter. However, when a large hole ([Formula: see text] diameter) was placed in the wall separating the two combustion chambers, synchronous initiation was successful. Synchronous initiation was also successful when the wall height was lowered (7-mm height). Under both conditions, the same level of specific impulse was achieved as for RDEs operating at the same mass flux.
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Combustion and Flame 264 113443-113443 2024年6月
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Journal of Spacecraft and Rockets 1-11 2024年5月28日There are few experimental studies on rotating detonation engines (RDEs) with liquid propellants. This study reveals the static thrust performance of a cylindrical RDE with ethanol and liquid nitrous oxide as propellants under atmospheric pressure. This RDE had an inner diameter of 40 mm, a maximum combustor length of 230 mm, a nozzle contraction ratio of 1.7, and a nozzle expansion ratio of 9.1. Nineteen experiments were conducted at total mass flow rates of [Formula: see text], mixture ratios of 3.6–5.9, and combustion pressures of 0.35–0.46 MPa, resulting in a maximum detonation velocity of [Formula: see text] (approximately 80% of the theoretical detonation velocity, [Formula: see text]), maximum thrust at sea level of 294 N, and maximum specific impulse at sea level of 148 s. In addition, the maximum characteristic exhaust velocity, [Formula: see text], was [Formula: see text], which was 99% of the theoretical value. The characteristic length of the combustion chamber at this time was 0.15 m. Since conventional rocket combustion requires 1.57 m to achieve the same [Formula: see text] efficiency, this study shows that detonation combustion can reduce the combustor size by 88%.
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Journal of Evolving Space Activities 71(2) 67-77 2024年3月 査読有り
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Proceedings of the Combustion Institute 40(1-4) 105735-105735 2024年
MISC
206-
Transactions of the Japan Society for Aeronautical and Space Sciences 53(180) 84-90 2010年To propel a spacecraft away from the Sun, a magneto plasma sail (MPS) spacecraft produces an artificial magnetic cavity to block the hypersonic solar wind. To make a large magnetic cavity sufficient to obtain significant thrust, the MPS spacecraft increases the magnetic cavity size using an onboard coil with assistance from a plasma jet. This process is called magnetic field inflation. In this study, we performed ideal and resistive magneto hydrodynamic (MHD) analyses to investigate the magnetic diffusion effect on the magnetic field inflation process. Our results indicate that a dipole-like magnetic field is drastically deformed by a plasma jet when the magnetic Reynolds number Rm was 10 or more, the magnetic field lines were nearly identical to the streamlines of the plasma jet. Hence, no magnetic diffusion effect appeared for Rm > 10. Meanwhile, when Rm is an order of unity, the magnetic diffusion effect was remarkable in the current sheet formed around equatorial region. For example, when the divergence angle of a plasma jet in the polar direction was 30°, the magnetic field strength at 40m from the spacecraft (calculated by resistive MHD model) was 19% smaller than the ideal MHD model (Rm=∞). © 2010 The Japan Society for Aeronautical and Space Sciences.
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Transactions of JSASS Space Technology Japan 8 Vol. 8, (2010) pp. 2010年
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Transactions of JSASS Space Technology Japan 8 Pb_19-Pb_25 2010年
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Advances in Applied Plasma Science 7 107-110 2009年8月20日
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47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2009年In rocket flights, ionized exhaust plumes from solid rocket motors may interfere with RF transmission under some conditions. In order to clarify the important physical process involved, microwave attenuation and phase delay due to rocket exhaust plumes were measured during sea-level static firing tests conducted on two types of full-scale solid propellant rocket motors. The measured data were analyzed by comparing them with numerical results such as flowfield simulations of exhaust plumes and by employing a detailed analysis of microwave transmission by using a frequency-dependent finite-difference time-domain (FD2TD) method. The results revealed that either the line-of-sight microwave transmission through ionized plumes or the diffracted path around the exhaust plume mainly affects the received RF level, which depends on the magnitude of the plasma RF interaction. For the actual launch vehicle flight, the transmission process is dominated by the diffraction effect so that we applied a two-dimensional diffraction theory to analyze the communication between a vehicle and a ground station. The attenuation levels estimated using diffraction theory agree with the data recorded in-flight. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc.
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AIP Conference Proceedings 1084 754-759 2009年 査読有りMagnetic sail (MagSail) is a deep space propulsion system, in which an artificial magnetic cavity captures the energy of the solar wind to propel a spacecraft in the direction leaving the sun. For a scale-model experiment of the plasma flow of MagSail, we employed a magnetoplasmadynamic arcjet as a solar wind simulator. It is observed that a plasma flow from the solar wind simulator reaches a quasi-steady state of about 0.8 ms duration after a transient phase when initiating the discharge. During this initial phase of the discharge, a blast-wave was observed to develop radially in a vacuum chamber. When a solenoidal coil (MagSail scale model) is immersed into the quasi-steady flow where the velocity is 45 km/s, and the number density is 1019 m-3, a bow shock as well as a magnetic cavity were formed in front of the coil. As a result of the interaction between the plasma flow and the magnetic cavity, the momentum of the simulated solar wind is decreased, and it is found from the thrust measurement that the solar wind momentum is transferred to the coil simulating MagSail. © 2009 American Institute of Physics.
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AIP Conference Proceedings 1084 721-+ 2009年 査読有り
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Journal of Physics: Conference Series 154 2009年 査読有りDECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the planned Japanese space gravitational wave antenna, aiming to detect gravitational waves from astrophysically and cosmologically significant sources mainly between 0.1 Hz and 10 Hz and thus to open a new window for gravitational wave astronomy and for the universe. DECIGO will consist of three drag-free spacecraft, 1000 km apart from each other, whose relative displacements are measured by a differential Fabry-Perot interferometer. We plan to launch DECIGO in middle of 2020s, after sequence of two precursor satellite missions, DECIGO pathfinder and Pre-DECIGO, for technology demonstration required to realize DECIGO and hopefully for detection of gravitational waves from our galaxy or nearby galaxies. © 2009 IOP Publishing Ltd.
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Laboratory Experiment of the Interaction between Plasma Flow and Magnetosphere of Magnetoplasma Sail衝撃波シンポジウム講演論文集 2007 57-60 2008年3月17日
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26th International Symposium on Rarefied Gas Dynamics, 2008/7/21-25, Kyoto, 784-789 2008年 査読有り
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44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2008年 査読有り
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Journal of Physics: Conference Series 122 2008年 査読有り
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日本地球惑星科学連合大会・ J250-P001（ポスター）・ 幕張メッセ・ 千葉 2007年5月
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Collection of Technical Papers. 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Vol.8, 2007 8 8410-8418 2007年
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宇宙航空研究開発機構・情報・計算工学センター・衛星環境プラズマ数値シミュレーションワークショップ報告書,宇宙航空研究開発機構特別資料,JAXA-SP-06-014, pp. 100-110 2007年 査読有り
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宇宙航空研究開発機構・情報・計算工学センター・衛星環境プラズマ数値シミュレーションワークショップ報告書, 宇宙航空研究開発機構特別資料,JAXA-SP-06-014, pp. 111-121 2007年 査読有り
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JAXA-SP-06-19 1-81 2006年3月
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磁気プラズマセイルの推力発生メカニズムの解明,JAXA RR (Research and Development Report) -05-014, Edited by I. Funaki and H. Yamakawa 2006年 査読有り
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JAXA RR (Research and Development Report) -05-014, Edited by I. Funaki and H. Yamakawa 2006年 査読有り
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Collection of Technical Papers - AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference 11 8669-8682 2006年 査読有りIn order to simulate the interaction between the artificially deployed magnetic field produced around a magnetic sail spacecraft and the solar wind, a laboratory simulator in a space chamber was designed. As a solar wind simulator, a high-power magnetoplasmadynamic arcjet was operated in a quasisteady mode of about 0.8 ms duration to provide a high-speed hydrogen plasma plume of about 0.7 m in diameter, which is accelerated to above 20 km/s with high plasma densities around 1017-1019 m-3. Into this high-density and high-velocity plasma jet, a small coil of 2-cm-diameter was immersed to obtain 1.9-T magnetic field at the center of the coil. These devices are operation in a large 2-m-diameter space chamber, and the formation of a magnetic cavity was observed around the coil. From the analysis of scaling parameters, it is found that the laboratory experiment of the plasma flow around the coil of the magnetic sail corresponds to a sub-Newton-class magnetic sail.
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ISAS Research Note, Vol. 789 2005年 査読有り
主要な書籍等出版物
6講演・口頭発表等
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第63回航空原動機・宇宙推進講演会／北部支部2024年講演会ならびに第5回再使用型宇宙輸送系シンポジウム 日本航空宇宙学会
共同研究・競争的資金等の研究課題
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日本学術振興会 科学研究費助成事業 基盤研究(B) 2017年4月 - 2021年3月
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日本学術振興会 科学研究費助成事業 挑戦的研究(萌芽) 2019年6月 - 2021年3月
