基于马赫线切割的楔形乘波前体改进设计研究

Improved Design of Wedge-Derived Waverider Forebody Based on Mach Line Cutting of Compression Surfaces

关键词:  乘波前体  马赫线切割  进气道流动  改进设计

Key words:  Waverider forebody  Mach line cutting of compression surfaces  Inlet flow  Improved design

摘要:

为了改善楔形乘波前体两侧大下反角对其横航向静稳定性的不利影响，利用马赫线切割方法对其进行了改进设计。该方法为在不影响进气道入流的条件下，对前体预压缩面的改进提供了基础。通过斜激波关系式求出了后掠斜楔激波脱体的临界参数，将其应用于楔形乘波前体的改进，使改进后的外形仍具有乘波特性。使用以上方法对典型楔形乘波前体开展了改进设计，采用数值模拟方法对改进外形进行计算分析。结果表明无粘流场中进气道入流区域的流场与原楔形乘波前体完全一致，无粘升阻比有所提高；同时，改进外形的横航向静稳定性与原楔形乘波体相比有明显改善。粘性数值模拟结果显示改进外形在有粘条件下仍具有较好的乘波特性和升阻比。

Abstract:

In order to improve the detrimental impact on lateral static stability caused by the large negative-dihedral angle of the wedge-derived waverider forebody， the improved design based on the Mach Line Cutting of Compression Surfaces (MLCCS) was developed. The MLCCS principle provided the basis for improving the compression surfaces of the inlet without affecting the inlet flow. The critical parameters for the shock wave detached from the leading edge of swept wedges were obtained by the oblique shock equations. And the parameters were used in the improved design to guarantee the attached shock wave. The improved waverider forebody was designed and numerical simulations were taken. The inviscid results show that the uniform pre-compression inflows provided by the wedge-derived and the improved waverider forebodies are identical， and the lift-to-drag ratio increased. The lateral static stability of the waverider forebody gets an effective improvement. And the shock is still attached to the leading edge of the improved waverider forebody. The viscous results indicate that the improved waverider forebody still have higher lift-to-drag ratio than the wedge-derived waverider forebody， and the shock is just detached from the leading edge for a short distance.