小林 弘明

First flight testing of Balloon-based Operation Vehicle (BOV) was carried out in 2006 and succeded. Second flight testing with a wing-body configuration will be done by a high-altitude balloon and dropped in September, 2006. Various types of onboard experiments such as a microgravity experiment and a demonstration of a supersonic engine are planned during flights for the third, fourth, and fifth flights. The aerodynamics load and characteristics of BOVs have been obtained by the CFD simulations as well as by the wind tunnel testing in ISAS. In this paper, the numerical simulations for BOV are presented and the results showed that the non-linear interaction between the wings, body, and engine exists for high angle of attack.

パルスデトネーションエンジンを航空宇宙用空気吸い込み式推進機関へ利用することを想定し，空気吸い込み式ＰＤＥの推力性能を見積もった．ＰＤＥは，供給圧が外気圧（大気圧）まで膨張するため，高空で作動する場合，推重比が低下する．この推力低下を軽減するため，新概念ＰＤＥを提案した．ＰＤＥの出口に高速開閉弁を設け，燃料充填時に弁を閉じることにより，高速飛行時のラム圧力をＰＤＥの推力に有効に利用する．さらに，インテーク捕獲流を燃料を利用して予冷却することにより，エンジン飛行可能領域がM0.5上昇する．これらのシステム解析の結果を踏まえ，PDRJE(Pulse Detonation Ramjet Engine)を提案した．さらに，ＰＤＥの基本的な推進性能について調査することを目的として，水素・酸素ＰＤＥの燃焼実験を実施した．ＰＤＥ燃焼器に作用する熱流束は5kW/m²/Hzであった．

TSTO統合最適設計手法の高度化として，最初に，TSTO周りの流れ場のCFD解析を行い，その結果をもとに新たに空力評価モデルを構築した．その結果，結合時にはBooster，Orbiter間で強い空力干渉が存在することが確認され，高精度な空力評価モデルの重要性が示唆された．この空力評価モデルをTSTO離陸重量最小化問題に適用し最適化計算を行った結果，従来のモデルを用いた場合に比べて新たに構築された高精度モデルを用いた場合の方が最適化計算によって得られる離陸重量が大きくなった．さらに，本問題を分離時間最小化を加えた多目的最適化計算を行い，その結果，離陸重量と分離時間のトレードオフ関係を支配するのは超音速飛行時の捕獲空気流量を制御する推進パラメーターであることが確認された．

Experimental Study of a variable geometry axisymmetric air intake (inlet) for ATREX engine has been done at ISAS supersonic wind tunnel and NASA GRC 1-by 1-foot supersonic wind tunnel since 1993. More than 13knds of subscale intake models whose cowl inlet diameter is 123 mm are tested and intake aerodynamic performances such as total pressure recovery and mass capture ratio are obtained. Each intake has the peculiar characteristics such as high mass capture type, high total pressure type. Some of these intakes attained the target of the development study from the viewpoint of intake aerodynamic performances at the limited Mach number range. The configuration of the supersonic diffuser passage is designed using the computer program that employs the method of characteristics and the configuration of the subsonic diffuser passage is designed using the axisymmetric CFD. The performances under off-design condition are also investigated by the CFD in parallel with the wind tunnel tests. By several trials of design and tests, intake design method was established. Furthermore off-design performances such as the bleed pattern of the spike and the cowl, the shape of the spike and the cowl tip, spike boundary layer transition point, and the angle of attack are investigated. And several proposals to improve the aerodynamic performances are done. Because the boundary layer on the spike is thicker than the cowl, bleed from the spike is more important to improve the total pressure recovery. A boundary layer transition system at the tip of the spike is necessary for the flyable intake model.