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基于单元塞式喷管的实验数据,研究了底部二次流对塞式喷管性能和底部特性的影响,测得了不同环境反压下塞锥表面的压强分布。实验表明,底部在不同压比下具有不同的气动状态。二次流的注入使底部开闭过渡点的压比值升高,底部开始提供推力的压比值下降,有利于避免底部开闭过渡时推力出现较大幅度降低。二次流流量达到主流的2.0%后,再加大底部二次流流量不再影响底部压强,过多地注入反而会降低塞式喷管的总体效率,1.5%~2.0%主流流量的二次流注入是比较好的选择。在低压比范围,塞锥表面有压强峰出现,随着高度的增加,压强峰后移并强度减弱。
Based on the experimental data of the unit plug nozzle, the effect of the bottom secondary flow on the performance and bottom characteristics of the plug nozzle was studied. The pressure distribution on the surface of the plug cone under different ambient back pressure was measured. Experiments show that the bottom has different aerodynamic conditions under different pressure ratios. The inflow of secondary flow makes the pressure ratio at the transition point at the bottom open and the pressure ratio at the bottom to provide the thrust decreases, which helps to avoid a substantial decrease of the thrust at the bottom opening and closing transition. After the secondary flow reaches 2.0% of the mainstream, it increases the pressure at the bottom of the secondary flow no longer affects the bottom pressure. Too much injection will reduce the overall efficiency of the nozzle and 1.5% -2.0% of the secondary flow Stream injection is a better choice. In the range of low pressure ratio, there is a pressure peak on the surface of the plug, and as the height increases, the pressure peak moves backward and the strength decreases.