This work develops a computational analysis framework of an axisymmetric two-stream nozzle for wrap-around combined cycle engines from the aspects of contour design methodology, design feasibility, and performance augmentation technology. This research proposes a modular design method that combines the inverse design for upstream turbojet/ramjet nozzles and the maximum thrust design for the collective mixing region based on the method of characteristics. An improved algorithm for the inviscid slip line is proposed on requirement to model the inevitable mixing layer between the two streams in mixing region. The validation and verification benchmarks confirm the robustness, accuracy, and effectiveness of the method from theoretical and practical perspective. The influences of the exit flow patterns and geometric conditions on the inverse design reveal its practicability boundaries, and it refines a direct judgment criterion with the verified credibility for the rational flow matching in the combined nozzle. The thrust and economic characteristics in relation to the flow patterns of upstream nozzle exits are further investigated. Results indicate that greater levels of linear exit flow angle distributions benefits both thrust coefficient and thrust–area ratio, with performance increments exceeding 6.35% and 43.76%, respectively, when the flowfield is transformed from the “shock-free” to “shock-induced” state.

本工作从轮廓设计方法、设计可行性和性能增强技术等方面开发了一种用于环绕式联合循环发动机的轴对称双流喷嘴的计算分析框架。本研究提出了一种模块化设计方法，将上游涡喷/冲压喷气喷管的逆向设计与基于特征法. 针对混合区两股流之间不可避免的混合层建模需求，提出了一种改进的无粘滑移线算法。验证和验证基准从理论和实践角度确认了该方法的稳健性、准确性和有效性。出口流型和几何条件对逆向设计的影响揭示了其实用性边界，为组合喷管内的合理流动匹配细化了一个经过验证的可信度直接判断准则。进一步研究了与上游喷嘴出口流动模式相关的推力和经济特性。结果表明，更高水平的线性出口流角分布有利于推力系数和推力面积比，