基于弯曲激波特征线法的两级压缩内收缩流场设计与分析

进气道是超声速飞行器的关键部件，设计核心是无黏超声速流场的确定，而波系结构又直接决定了流场的性能。考虑到实际应用价值，基于给定激波的超声速流场反设计至关重要。传统单道入射波的流场结构简单，压缩效率不高，且传统特征线法（method of characteristics，MOC）无法获得高阶的气动参数。为了拓展设计思路，首先利用弯曲激波特征线法展示了内收缩超声速流场不同的单元过程，随后基于此法提出了一种已知入射和反射激波的两级压缩内收缩流场的概念及反设计方法。基于此法设计的基准流场与数值模拟结果吻合良好，双入射激波可以提高压缩效率并缩短长度，能够实现波系结构和出口参数的分布可控，在非均匀来流条件下也能得到相应型面。在给定激波的条件下，求解分析了一系列具有中心体的轴对称流场，讨论入射和反射激波激波角分布对流场气动参数和几何参数的影响。弯曲激波特征线法的精确性和有效性使其成为平面/轴对称超声速流场反设计的良好候选。 

Design and Analysis of Two-Stage Compression Internal Flowfield Based on Method of Curved-Shock Characteristics

The inlet is one of the key components of the supersonic vehicle. The core of its design is the determination of the inviscid supersonic flowfield. The wave structure directly determines the flowfield performance. Considering the practical application, the inverse design of the supersonic flowfield based on given shocks is of vital importance. The traditional flowfield with a single incident shockwave is simple but its compression efficiency is not high. The method of characteristics (MOC) can not obtain high-order aerodynamic parameters. To expand design patterns, this paper firstly used the method of curved-shock characteristics to illustrate different unit processes of the internal supersonic flowfield. Then the concept and inverse design method of a two-stage compression internal flowfield with pre-assigned incident and reflected shocks were proposed. The corresponding flowfield designed on the basis of this method is in great agreement with numerical results. The dual incident shock waves can improve the compression efficiency and shorten the compression length. This method can realize the controllable distribution of the wave structure and outlet parameters simultaneously. Even under the conditions of the non-uniform incoming flows, the corresponding profile can be obtained. With given shocks, a series of axisymmetric flowfields with a centerbody were solved and analyzed. The influence of the incident and reflected shock angles on aerodynamic and geometric parameters of the flowfield was discussed. The accuracy and efficiency of the method of curved-shock characteristics make it a good candidate didate for the inverse design of plane/axisymmetric supersonic flowfield.