辅助活门对串联TBCC排气系统的影响研究

在低落压比状态下,对有无辅助活门的两种串联式TBCC组合喷管开展了数值模拟计算,并对包含辅助活门的串联式组合喷管进行了实验研究,通过分析其壁面沿程压力分布与波系结构的变化情况,探究辅助活门对串联式组合喷管气动性能的影响。结果表明：辅助活门结构减少主流喷管外壁面的流动分离区范围,有效的提高了组合喷管内推力。带辅助活门型组合喷管能够引射环境气流,减少引射喷管壁面的回流区范围与底部阻力,从而减少推力损失,提升组合喷管整体性能。提高次流压比或降低主流压比,主流喷管出口处欠膨胀程度降低,声速线往下游方向移动,主流流量减少。提高主流压比或者次流压比都能使辅助活门引射环境气流量增加。辅助活门进气通道距离会改变次流射流与引射喷管的相对位置,距离过小或过大都会造成引射环境流体流量减小。

Effects of Auxiliary Door on Tandem TBCC Exhaust System

In the low nozzle pressure ratio state, numerical simulation calculations were carried out for two sets of tandem combination nozzles with and without auxiliary doors, and the tandem combined nozzle with auxiliary doors was also experimentally studied. The influence of auxiliary door on the aerodynamic performance of tandem combined nozzle was explored by analyzing the variation of the pressure distribution along the wall surface and the structure of wave system. The results show that the auxiliary door structure can reduce the range of the flow separation area on the outer wall surface of the mainstream nozzle, and effectively increase the internal thrust of the combined nozzle. The combination nozzle with auxiliary doors can inject ambient airflow to reduce the range of the back-flow zone and bottom drag of the injection nozzle wall, thereby reducing thrust loss and improving the overall performance of the combination nozzle. Increasing the secondary flow nozzle pressure ratio or reducing the mainstream nozzle pressure ratio reduces the degree of under-expansion of mainstream at the throat of the mainstream nozzle. The sonic line moves downstream, and the mass flow rate of mainstream decreases. Increasing the mainstream nozzle pressure ratio or the secondary flow nozzle pressure ratio can increase the mass flow rate of ambient gas injected by the auxiliary door.The distance of the inlet passage of the auxiliary door will change the relative position of the secondary flow jet and the ejector nozzle. If the distance is too small or too large, the mass flow rate of the environment fluid will be reduced.