Aerodynamic Design Of Bleed Flow Turbine Integrated On Hypersonic Near Spacecraft

The high-altitude and remote mode has showed a strong advantage in the modernwarfare. With the development of space technology, the near space aircraft hashighlighted its advantage in communication support, space countermeasure andstrategic strike. As a result, the energy supply for the near space aircraft has become aworld-wide research hotspot. This paper studies the small-sized andexternally-mounted bleed flow turbine in terms of the characteristics of hypersonicnear space aircraft, for the purpose of realizing the effective and stable conversionamong aerodynamic energy, mechanical energy and electrical energy generated duringhigh-speed flight, and breaking the limitation in the use of traditional battery and solarcell on the near space aircraft, thus supplying energy for airborne equipment and othersensors during the long-time flights.In this paper, an aerodynamic design method of the bleed flow turbine which willwork in the condition of hypersonic and big inlet distortion is discussed. Initially,numerical simulation is put on the near space aircraft integrated with a bluff bodyinstead of a real turbine so as to estimate the impact of the bleed flow turbine on theaircraft. As a result, the working condition of the bleed flow turbine could be got tostart the one-dimensional parameter calculation. On this basis, two-dimensional andthree-dimensional aerodynamic design is carried out. In the process of seeking anappropriate blade shape and stacking rules, the design guidelines such as small leadingedge, thin trailing edge and linear bevel portion are proposed. In order to reduce theimpact of the shock wave, the forward-swept method is adopted. In addition, theimpact of the blunt head of the turbine is studied. The result indicates that themaximum output power of the turbine emerges when sweet angle is10°and blunt angleis30°. By means of verifying and improving the turbine performance based on theintegrated coupling calculation of the bleed flow turbine and the aircraft, and alsotaking into consideration of the influence on the performance of the near space aircraftand other factors like the uniformity of air intake, the final design that could meet therequirements on power output is proposed.The following work in this paper focuses on adjusting the output power throughchanging the angle of deflection and frontal area of the turbine to guarantee a stable output power in different conditions. On this basis, the relationship between the outputpower and frontal area is studied, and then realizing the purpose of automaticadjustment without feedback according to the numerical fitting of the results. Finally,the interference effect between the bleed flow turbine and hypersonic near spacecraftand the flow evolutional mechanism are analyzed, and the effect on lift and dragcoefficient, yawing moment coefficient, pitching moment coefficient during the poweroutput self-stabilization of the turbine is discussed.