著者
永田 晴紀
出版者
日本混相流学会
雑誌
混相流 (ISSN:09142843)
巻号頁・発行日
vol.27, no.4, pp.393-400, 2013-12-15 (Released:2014-01-17)
参考文献数
9
被引用文献数
1

A liquid oxygen supply system for a small-scale sounding rockets was developed. The sounding rokets are hybrid type employing a combination of plastics (PMMA or high density polyethylene) and liquid oxygen as propellants. Key points for the miniaturization were using no valve in the liquid oxygen feeding line and omitting precooling treatment of the line. Without precooling treatment, the liquid oxygen in the feeding line becomes multiphase flow until the temperature of the feeding line falls below the boiling temperature of the liquid oxygen. A characteristic time of multiphase flow duration was proposed to evaluate the duration a multiphase flow holds in the feeding line. Static firing tests showed that the multiphase flow ends within the half the characteristic time, showing that the liquid oxygen flow rate history without a precooling treatment is acceptable for an actual operation of the rocket motor. Finally, an impinging type injector was developed to remove a combustion instability, caused by a coupling of the combustion chamber pressure and the propellant (liquid oxygen) feed system.
著者
澤井 秀次郎 坂井 真一郎 坂東 信尚 丸 祐介 永田 晴紀 後藤 健 小林 弘明
出版者
国立研究開発法人宇宙航空研究開発機構
雑誌
基盤研究(A)
巻号頁・発行日
2013-05-31

本研究の目標は,空気吸い込み式エンジンを用いるスペースプレーンの実現に向けて,飛行実証を通して基盤となる技術を獲得することにある.そのために,気球による高高度からの落下と無火薬式の小型ロケットブースターによる加速を組み合わせた,低コストの高速飛行実証手段を構築する.本研究では,飛行実験システムの検討・試作を行い,最終的に飛行実験を行って実験システムの有効性を実証することを目指す.また,実験システムの試作研究を通して,スペースプレーンの実現に必要な技術の研究を実施する.H28年度は,1. 高速飛行実験システム検討,2. 飛行実験機の試作研究,3.スペースプレーンの実現に必要な技術の研究として空力設計技術の研究,を行った.1では,実験機形態の風洞実験によって取得された,マッハ数や操舵角をパラメータとする空力特性を用いて飛行実験軌道検討を行った.到達高度や運用制約など,気球I/F条件を具体的に考慮した.その結果,気球を利用したシステムにおいては,気球の到達高度が全体の性能を決める要因であることが明らかになった.気球実験機会の獲得に向けた活動を実施してきているものの,機会獲得には至っていないなかで,地上試験での機能検証を進めるべく実験計画検討を進めた.地上で一連のシーケンスを実時間で流す実験を立案した.2では, (1)試作を行ってきた実験機構造の機械噛合せを行い,その結果を受けた調整や改修を行った.(2)アビオニクスの電源分配機能および電源・信号ハーネスの検討を実施した.(3)飛行実験シーケンスの具体化に沿って,ソフトウェアの開発を進めた.3では,空力設計技術に関して,スペースプレーンの空力形状としてウェーブライダーの特性を利用することを考えている.今年度は,ウェーブライダーに単純な可変機構を設けることで非設計点性能を改善するアイディアに関する研究を行った.
著者
永田 晴紀 飯島 直純 金井 竜一朗
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.54, no.170, pp.251-258, 2012 (Released:2018-01-26)
参考文献数
9

During large scale CAMUI-type motor development, the authors frequently encountered anomalous combustion, a sudden pressure increase leading to destroy of the motor. Repeated static firing tests finally revealed that the cause of the anomalous combustion is the low initial fuel temperature. However, the mechanism responsible for the anomalous combustion is still unclear. Although a series of firing tests with a small combustor could not reproduce the anomalous combustion successfully, results showed a clear correlation between the initial fuel temperature and chamber pressure overshoot; chamber pressure overshoot does not occur when the fuel temperature is above the Leidenfrost point. From this result, the authors offer a hypothesis that the low fuel temperature below the Leidenfrost point enhanced heat transfer from the fuel to liquid oxygen and caused local blowoff. Accumulation of combustible mixture follows the blowoff and may cause the anomalous combustion. A possible reason why the firing tests could not reproduce the anomalous combustion is that Damkohler number in the combustion chamber was larger than those in the large-scale CAMUI-type motors. A preliminary experiment showed that the small combustor could reproduce the anomalous combustion by decreasing the Damkohler number in the combustion chamber. Detailed experimental study will follow the preliminary experiment to clarify the mechanism of the anomalous combustion.
著者
石山 達也 戸谷 剛 永田 晴紀 稲場 康彦 井上 遼太 佐々木 俊也 寺川 健 桧物 恒太郎 李 尚駿 金井 竜一朗 脇田 督司
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.2012, pp._S192023-1-_S192023-5, 2012

Although many groups are developing Cansat, a can-sized mock satellite, they have few opportunities to test due to difficulties for students to launch Cansats domestically. To provide the chance to launch Cansats, the authors downsized CAMUI type hybrid rocket and created easy-to-use launch system. The new launcher, miniCAMUI, uses gas oxygen (GOX) as oxidizer and high density polyethylene as fuel. Using GOX instead of liquid oxygen contributes to downsizing and weight saving, reduction of turnaround time for launch due to the simplified procedure to fill the oxidizer. A GOX tank connects to a motor through a valve. An air-driven actuator operates the valve miniCAMUI was launched 6 times in June and July 2012. Three of them were serial successful launches with two rockets in a day, with a turnaround time about 45 minutes. Two of the three launches were with the same rocket in the day. With the wind velocity of 1 to 2 m/s, the apogee altitude was about 74 m, being very close to the predetermined altitude of 80 m. This result shows that miniCAMUI was successfully developed as a small launch system with high operability. miniCAMUI is available for launches to various altitudes below 250 m.
著者
永田 晴紀
出版者
北海道大学
雑誌
挑戦的萌芽研究
巻号頁・発行日
2015-04-01

著者らは、軸方向に多数の微小ポートを有する固体燃料のポート出口端面で微小拡散火炎群を保持する「端面燃焼式ハイブリッドロケット」を提案してきたが、燃料の製作が困難なため実証実験を見送って来た。近年の3Dプリンタの発展により複雑な燃料形状が製作可能となり、世界で初めて端面燃焼式ハイブリッドロケットの実証実験を実施した。燃焼実験の結果、初期の非定常期間を経て、燃焼中に燃料-酸化剤比が一定に保たれる定常燃焼への移行が確認された。ポート内径が0.2~0.5 mmの単ポート燃料試料を用いた燃焼実験も実施した。燃え広がり燃焼と安定燃焼の2つのモードが観察され、両モードを分ける臨界摩擦速度が確認された。
著者
野原 正寛 金子 雄大 萩原 俊輔 永田 晴紀
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:18848346)
巻号頁・発行日
vol.77, no.777, pp.1249-1258, 2011 (Released:2011-05-25)
参考文献数
6

The authors have been developing Cascaded Multistage Impinging-jet (CAMUI) type hybrid rockets. A CAMUI type hybrid rocket uses a fuel grain consisting of several cylindrical fuel blocks with two ports. To minimize both of c* loss due to O/F shifting and residual fuel weight after burning, an appropriate design of initial fuel grain shape is necessary. However, obtaining an optimum design of initial grain shape is not easy because there are many design variables influencing one another. To solve this problem, the authors employed Genetic Algorithm (GA) combined with a numerical model forecasting performance history of a CAMUI type motor. GA can acquire an approximate optimum solution for problems with a vast search space in practical time. The numerical model gives c* loss and residual fuel weight to evaluate the degree of performance of each initial fuel grain shape. A fuel grain design proposed by this method showed residual fuel weight as small as 6.36% of the initial weight and c* loss less than 1%.
著者
新井 隆景 遠藤 彰 永田 晴紀 杉山 弘 森田 修至
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.63, no.614, pp.3318-3324, 1997-10-25
被引用文献数
7 1

Supersonic combustion using a catalytic combustion in a cold supersonic flow field was investigated in a square duct with a backward-facing step. The free stream Mech number was M_m=1.81. Hydrogen was injected transversely behind a backward-facing step into a cold air free stream. Using a catalyst in a cold supersonic turbulent mixing layer, it was found that hydrogen reacted stably to oxygen in the air flow. The relationship between the heat release due to catalytic combustion and supersonic flow properties, which influence the supersonic combustion, was clarified experimentally. The spatial distribution of heat release generated by catalytic combustion in the supersonic turbulent mixing layer is discussed. It was found that the heat release due to the catalytic combustion had a maximum at the outer edge of the mixing layer.
著者
岸田 耕一 金子 雄大 大島 伸行 永田 晴紀
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.765, pp.789-794, 2010-05-25

This paper investigates a thermal-fluid dynamics of CAMUI (Cascaded Multistage Impinging-jet) type hybrid rocket developed in Hokkaido University by using a large eddy simulation of turbulence. The performance of the hybrid rocket is sensitive to the changing shape of its chamber. To clarify this effects, numerical simulations were conducted using measured shapes. The results show the flow structures such as impinging fountain flow depending on the shapes at different burning time. Thease structures generate the particular heat flux distributions on the surface.
著者
永田 晴紀 渡辺 三樹生 伊藤 光範 前田 剛典 戸谷 剛 工藤 勲
出版者
一般社団法人日本機械学会
雑誌
スペース・エンジニアリング・コンファレンス講演論文集 : Space Engineering Conference (ISSN:09189238)
巻号頁・発行日
vol.2004, no.13, pp.1-4, 2005-01-20

Small-scale reusable sounding rocket system is under development to provide means of stratosphere observation and three-minutes microgravity experiment. The propulsion system is a hybrid type that uses solid fuel (plastics) and liquid oxygen as propellants and free from explosives, resulting in the dramatically reduced launch cost. To enhance the burning rate of the solid fuel and to augment the thrust, the rocket has employed a new fuel grain design. This new design, named CAMUI as an abbreviation of "Cascaded Multistage Impinging-jet", allows mixing and combustion to occur around stagnation points on fuel surfaces. Successful launch experiments using a 50-kgf CAMUI engine have proved the feasibility of the basic idea of the system. Finally, possible configurations of the stratosphere observation vehicle and the microgravity test vehicle are presented.
著者
秋葉 鐐二郎 青木 嘉範 加勇田 清勇 藤井 篤之 永田 晴紀 佐鳥 新
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会論文集 = Journal of the Japan Society for Aeronautical and Space Sciences (ISSN:13446460)
巻号頁・発行日
vol.51, no.591, pp.141-150, 2003-04-05
参考文献数
11
被引用文献数
1 2

The staged combustion hybrid rocket is under development by our research group since 1999. This hybrid rocket engine consists of two combustion chambers. The primary combustion chamber is the fuel tank itself filled with granular solid fuels. The fuel rich gas generated by the first stage combustion flows into the secondary combustion chamber, which is located in the bottom of the primary combustion chamber. The additional oxidizer is injected to the secondary combustion chamber in order to attain an optimal specific impulse by completing combustion. There are two types of the primary combustion. One is nicknamed as the incinerator type; the other is called the multi-grain type. This new type engine is featured with a wide range throttling capability and an extensive freedom in selecting the fuel material. This paper deals with the incinerator type. Presented are preliminary experiments as well as the systems description.