双椭圆截面再入飞行器的气动计算及布局优化设计

双椭圆截面飞行器较圆截面回转体外形具有更好的刚性、更轻的重量、更大的容积和更高的配平升阻比.本文首先发展了一套可以计算该类飞行器纵横向气动力的工程计算方法,并利用N-S方程数值模拟方法进行了验证.其次,对此类飞行器的气动布局进行了优化设计,并利用相同的优化模型对圆截面外形进行了计算.最后,对双椭圆截面优化外形和圆截面优化外形的气动特性进行了比较.

Aerodynamics prediction and configuration optimization for reentry vehicle with double-ellipse cross-section

Traditionally reentry vehicles are designed to be axial symmetric, whereas vehicle with double-ellipse cross-section has a better rigidity, bigger volume, higher trimming lift and lift-to-drag ratio. Firstly, through the introduction of (equivalent) cone and equivalent cross-section, an engineering method based on Embedded Newtonian Flow Theory has been presented to predict the aerodynamic characteristics of this vehicle during hypersonic reentry flight. The comparison of the results with that of N-S equation numerical simulation shown that the accuracy of the presented method is sufficient for the conceptual design, and the correctness and effectiveness of the method are validated. Then a multiple objectives optimization technique has been introduce and applied to optimize the vehicle for higher trimming lift and lift-to-drag ratio together with the optimization for circle cross-section vehicle under the same constraints of equal length and base area. The optimum (results) shown that the vehicle with double-ellipse cross-section has higher lift and lift-to-drag ratio than the vehicle with circle cross-section as the angle of attack is higher than 7 degree. Finally, the comparison of lift-to-drag ratio and mass center displacement needed for trimming condition have been investigated. The stability of the vehicle with double-ellipse cross-section is higher than circle one, easer for the design of mass distribution, and is beneficial for the rolling control. The present work indicates that the reentry vehicle with double-ellipse-cross-section is one of the feasible choices for hypersonic maneuver, and need to be investigated further in the future.