Abstract: The experimental investigation of a Single Expansion Ramp Nozzle (SERN) in the condition of transonic flight was presented.A large flow separation was observed in the basic model SERN 1 without second flow injection. The thrust coefficient C fx of model SERN 1 is of low as to 0.29～0.58. With second flow injection into the expansion surface the separation region was greatly reduced while the thrust coefficient increased up to around 0.97. The optimized relative height of second flow throat A t2 = A t2 / A t1 was about 0.25 in the experimental situation.

Key words: Engine nozzle;Internal aerodynamics;Secondary flow;Nozzle flow

摘要： 通过风洞试验研究了平面二维非对称大膨胀比喷管跨声速飞行时的喷管特性。研究表明 ,无二次流的基准喷管在试验压比下 ,膨胀面气流严重分离 ,轴向力推力系数Cfx仅为 0 2 9～ 0 5 8。带二次流的喷管试验显示 ,二次流能有效地抑制喷管膨胀面气流的分离 ,改善喷管的总体性能。恰当地选择二次流气动参数 ,喷管的Cfx可以增加至 0 97左右 ,最大流量系数接近 0 99。在试验的条件下 ,最佳的二次流相对喉道高度约为 0 2 5。

关键词: 发动机喷管;内流空气动力学;二次流;喷管气流