关键词: 超燃冲压发动机, 单边膨胀喷管, 几何约束, 特征线法, 最大推力理论

Abstract: In view of the requirement of nozzle/afterbody integration, a new design method for scramjet nozzles with geometric constraints is proposed to optimize the nozzle aerodynamic performance. The proposed design method is investigated using numerical simulation, and its validity attested. Furthermore, the grid resolution is determined. The influence study of the two key design factors in the nozzle design process, i.e., the proportional factor and the asymmetric factor, is then conducted. Finally, comparative analysis of the proposed method and the typical truncation method is performed to verify the effectiveness and superiority of the new method. The results show that the new design method can obtain a nozzle satisfying the geometric constraints with the thrust coefficient, the lift, and the pitch moment increasing by 33.36%, 265.75% and 37.21% respectively. In addition, the design factors of this method can be adjusted to obtain nozzles with different aerodynamic performance to meet the actual requirements of the application.

Key words: scramjets, single expansion ramp nozzles, geometric constraints, method of characteristics, maximum thrust theory