2 0 0 0 OA ハイブリッドロケット起動時に発生する異常燃焼の機構解明
- 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.
1 0 0 0 ピントル型噴射器における燃焼振動挙動の光学計測
- 著者
- 榊 和樹 舩橋 友和 中谷 辰爾 津江 光洋 金井 竜一朗 鈴木 恭兵 稲川 貴大 平岩 徹夫
- 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 (ISSN:13446460)
- 巻号頁・発行日
- vol.65, no.5, pp.193-199, 2017
The longitudinal combustion instability characteristics of a pintle-type injector for a bipropellant rocket engine combustor are investigated experimentally. An optically accessible combustion chamber are used to observe unsteady combustion behaviors under oscillating combustion conditions. CH* chemiluminescence and backlit spray images are observed simultaneously with two high-speed cameras. Two experiments with the propellant total momentum ratio (TMR) of 0.76 and 2.48 are conducted, whereas the combustion pressure and the propellant mixture ratio are 0.45 and 1.6, respectively. The combustion oscillations at the natural frequencies of the chamber longitudinal acoustic mode are observed when the TMR is 0.76. The combustion oscillation is caused by the coupling between the heat release and the combustion chamber acoustics. When the TMR is 2.48, the combustion oscillations at the frequencies of 400 and 800Hz, which are lower than the first longitudinal mode frequency, are observed. Since the 400Hz corresponds to the convective time scale in the combustion chamber, the oscillations could be caused by one of the convective modes such as entropy wave.
- 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.