Abstract: In order to decrease the difference of cold/hot pitching moment，an optimization design method based on the Isight software，and integrated by using CFD and Non-dominated Sorting Genetic Algorithm(NSGAⅡ)，is applied to design for a cubic curve cowl of SERN. Then the interaction with the major geometric parameters (initial expansion angle and terminal angle) and their effects on the SERN performance are further investigated. The results show that，within the design range，the cubic curve cowl can ensure the SERN keep high thrust coefficient，and adjust the pitch moment within a wide range，change the difference of nozzle cold/hot pitch moment greatly at the same time. Finally a cold flow wind tunnel experiment of scaled model is carried out，and a numerical simulation is performed based on the conditions of the tunnel test. The results of the simulation are in good agreement with experiment data，which validates the effectiveness and correctness of the optimization method and the results of numerical simulation.

Key words: Single expansion ramp nozzle；Optimization design；Geometric parameters；Difference of pitch moment；Wind tunnel test

摘要： 基于Isight优化平台，将多目标遗传算法与CFD计算相结合，针对超燃冲压发动机非对称尾喷管冷/热态俯仰力矩差较大的问题，对下壁面为三次曲线的尾喷管构型进行多目标优化，分析了初始膨胀角和尾缘角的相互耦合及其对喷管性能影响所占比重。结果表明，设计区间内，下壁面三次曲线构型在保持较高推力特性的前提下，可以大范围调整喷管俯仰力矩，显著改善喷管冷/热态俯仰力矩差较大的问题。在此基础上，选取优化所得点进行冷流缩比风洞实验，根据实验条件进行了相应的数值模拟，对比发现数值模拟与实验结果吻合很好，验证了该优化设计方法及结果的有效性和可靠性。

关键词: 单膨胀斜面喷管；优化设计；几何参数；俯仰力矩差；风洞实验