喷管面积比对推力矢量发动机特性的影响

针对矢量喷管出口面积独立无极可调控制的特点，采用数值仿真分析了偏转状态喷管面积比对矢量特性的影响机理，通过整机地面台架和高空台专项试验，获取了不同喷管面积比下推力性能、偏转推力损失、偏转效率、发动机匹配特性等数据。结果表明：非偏转状态发动机产生最大推力的喷管面积比小于气流完全膨胀对应的理论喷管面积比。发动机偏转推力损失随几何矢量角增加而增大，喷管面积比对偏转推力损失影响较小。地面台架状态相同几何矢量角下，矢量偏转效率随着喷管面积比的增大而降低，当喷管面积比达到一定值时，会出现气流分离使偏转效率进一步降低。在相同几何矢量角下，随着喷管面积比的增大，发动机节流状态转差减小，风扇工作线下移，靠近非偏转状态工作线，风扇裕度增加，工程应用中偏转状态的扩稳措施应考虑与喷管面积比的关联。

Influences of nozzle area ratio on thrust vector engine characteristic

For the characteristic of the independent stepless control on the vectoring nozzle exit area, a numerical simulation was applied to analyze the nozzle area ratio effect mechanism on the vectoring characteristics. The data taken from ground platform tests and altitude facility tests provided various parameters consisting of the engine thrust performance, deflection thrust loss, deflection efficiency and engine matching characteristics under different nozzle area ratios. The results showed that, the nozzle area ratio of the maximum thrust in the non-deflected state was less than the nozzle area ratio under full expansion of the air flow. The engine deflection thrust loss increased with the rise of the geometric vector angle, but suffered less effects by the nozzle area ratio. When the geometric vector angle remained unchanged by the ground test, the vector deflection efficiency decreased with the rise of nozzle area ratio, and if it reached a certain value, the phenomenon of gas flow separation would result in a further decrease of deflection efficiency. Furthermore, during throttle working state by keeping the same geometric vector angle, the engine shaft speed difference reduced with the increase of nozzle area ratio. This would move down the engine fan co-operating line to the non-deflection co-operating line nearby, thus enlarging the fan surge margin. Therefore, it is quite necessary to investigate the effect of nozzle area ratio to the stability expansion approaches in the engineering application.