可变弯尾飞行器气动设计研究

On Aerodynamics-Related Overall Layout Considerations for Hypersonic Variable-Bend-Tail Vehicle

可变弯尾飞行器的气动方案是高超声速机动的潜在可行方案。利用内伏牛顿流理论计算分析了此类飞行器的高超声速气动特性 ,提出了气动设计的关键问题。采用加权多目标法和多目标遗传算法对此类飞行器进行了气动布局的优化设计 ,分别研究了配平条件下的升阻比和铰链力矩问题 ,以及铰链力矩、操纵效率与飞行器质心位置和弯尾部分长度的相互关系。研究表明 ,应通过合理的布局优化设计 ,使弯尾角等于或接近于其自由漂浮角 ,设计诀窍是使弯尾部分的质心及压心设计在弯尾的铰链轴上 ,即三心合一。合理的布局设计可以使可变弯尾飞行器具备弯尾控制效率高。

Variable bend tail concept may be one of the possible approaches for satisfying the maneuvering requirement of hypersonic reentry vehicle. We explore the aerodynamics related overall layout for hypersonic variable bend tail vehicle. Section 1 discusses the desirability of making hinge moment of such variable bend tail vehicle as close to zero as possible. Section 1 also discusses that there is a 'free float point' corresponding to each trimming angle that can make hinge moment as close to zero as possible; in order to make the variable bend tail vehicle fly at 'free float point' within a relatively large range of trimming angle, the design should ensure that the center of gravity of the tail and the center of pressure of the tail should be coincident and on the hinge axis. Section 2 deals with the optimization of aerodynamics related overall layout of variable bend tail vehicle. We performed optimization of aerodynamic configuration with weighting method and genetic optimization algorithm; in the optimization we paid due attention to taking lift to drag ratio into consideration. Figs.4, 5 and 6 give results of optimization. Section 3 gives a numerical example; the maneuvering performance results of a variable bend tail vehicle with aerodynamic configuration designed according to our optimization procedure, as shown in Figs.8 and 9, appear to be satisfactory.