著者
長谷川 裕晃 北原 一起 犬飼 保夫
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.50, no.582, pp.272-272, 2002 (Released:2003-09-02)
参考文献数
5
被引用文献数
2 or 0

The Air Turbo Ramjet (ATR) is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds and therefore the ATR is an attractive propulsion system for the wide operation range (e.g. Mach 0 to Mach 4). The ATR can provide a higher specific impulse than a solid fuel rocket engine and a higher thrust per frontal area than a turbojet engine. The major ATR components are the inlet, fan (compressor), turbine, gas generator, combustor and exhaust nozzle. In the ATR, the turbine drive gas is generated by a decomposed liquid or solid fuel gas generator. In order to carry heavier payloads and to attain shorter flight time, the compact and high thrust engine is required. In this study, the ram combustor with the double-staged flameholders and the fan with tandem blade were introduced to shorten the engine length and to increase the fan pressure ratio, respectively. Furthermore, the engine testing was carried out on sea level static condition to confirm the engine component integration technologies for the ATR propulsion system.
著者
中川 健一 長谷川 裕晃 村上 正秀 大林 茂
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 (ISSN:21879761)
巻号頁・発行日
vol.83, no.856, pp.17-00165-17-00165, 2017 (Released:2017-12-25)
参考文献数
13

Badminton is one of the most popular sports in the world and is famous as the sport having the fastest initial velocity of a batted ball among all ball games. Initial velocity immediately after smashing may reach up to 408 km/h (113 m/s) at maximum. A badminton shuttlecock generates significant aerodynamic drag and it was confirmed that the high deceleration characteristics was related to the slots located at the leg portion of a shuttlecock in the previous study. Turnover refers to the flipping experienced by a shuttlecock when undergoing heading change from nose pointing against the flight path at the moment of impact and a shuttlecock indicates the aerodynamically stable feature for the flip movement just after impact. The purpose of this study is to investigate the effect of gaps on the aerodynamic stability (turnover stability) of a badminton shuttlecock during the flip phenomenon. In the present study, the flow field around the shuttlecock during impulsive change of an angle of attack (flip movement) was measured by using the smoke flow visualization and the behavior of the shuttlecock during the flip movement was evaluated in comparison with that of the conic model (with no gaps). The turnover stability of a badminton shuttlecock is affected by gaps of the shuttlecock skirt.
著者
長谷川 裕晃 大津 里実
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.783, pp.2049-2057, 2011 (Released:2011-11-25)
参考文献数
20

The reverse osmosis (RO) method is a method obtaining the fresh water by using semi permeable RO membrane. However, the RO method has to give continuous operation at high pressure in seawater desalination plants. In the present study, in order to improve the efficiency of RO desalination under low pressure conditions, the water treatment system is proposed by using microbubbles in salt water disposal. Microbubbles are very small air bubbles with diameters of the order of less than several tens microns, and our proposed microbuble generator was developed in our previous study. The RO desalination efficiency can be improved by microbubble generation in salt water in contrast to the method with no microbubbles, and the efficiency of desalination is significantly improved by microbubbles with a high electrical potential. The effect of the microbubbles on the rate of osmosis was also investigated by measurements of the electric conductivity and the shrinkage rate of microbubbles. The electrical conductivity of salt water decreases with increasing the electrical property of the gas-water interface (ζ- potential) of microbubbles. Furthermore, microbubbles with a high electrical potential of high number density in salt water can exist in salt water because the rising velocity and the shrinkage rate of microbubbles become smaller with increasing the high electrical potential of microbubbles.
著者
長谷川 裕晃 塚本 義明 花田 忠之 田北 勝彦
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.50, no.581, pp.231-231, 2002 (Released:2003-09-02)
参考文献数
6

The application of ceramic components in gas turbine engines enables the improvement of the power output and the efficiency of gas turbines by increasing the turbine inlet temperature. The high temperature properties of the ceramic materials offer the potential of higher turbine operating temperatures with no cooling techniques and therefore the ceramic components with higher temperature limits are becoming more attractive. In this study, the ceramic turbine wheel is applied in the aircraft gas turbine engine and the engine testing is demonstrated under full load operating conditions. The successful testing of the ceramic turbine components in the aircraft gas turbine engine has been accomplished. The test results indicate that the ceramic turbine wheel is capable of operating under the high thermal shock condition of fast starting to full speed. Furthermore, the adoption of some new ceramic turbine design concepts is proposed in actual use for aircraft ceramic turbine engines.
著者
橋本 孝雄 長谷川 裕晃
出版者
一般社団法人日本機械学会
雑誌
ジョイント・シンポジウム講演論文集 : スポーツ工学シンポジウム : シンポジウム:ヒューマン・ダイナミックス : symposium on sports engineering : symposium on human dynamics
巻号頁・発行日
vol.2008, pp.201-203, 2008-11-05

In the present study, impact force measurements and biomechanical analysis were carried out during the KERI (kicking) of SHORINJI-KEMPO. The impact force and kinetic parameters were measured by using the proposed impact force measuring device with strain gages, accelerometer and three-dimensional rate gyro sensors. Furthermore, the force of pivot leg was measured by a 6 degree-of-freedom force sensor, and the movements of KERI-ASHI (moving leg during KERI motion) were measured by using accelerometer. The trained SHORTNJI-KEMPO players showed the larger impact force in contrast to that for un-trained players. The impact force was affected by the pivot leg movements. It is important to increase the impact force that the player supports the body with the toe side and the inside of the pivot leg and the body is stabilized by the large reaction force of pivot foot when the player starts the KERI motion.