辅助活门对串联TBCC排气系统的影响研究

Effects of Auxiliary Door on Tandem TBCC Exhaust System

关键词:  涡轮基组合循环发动机  排气系统  喷管  风洞实验  数值模拟  回流区  气动性能

Key words:  Turbine based combined cycle engine  Exhaust system  Nozzle  Wind tunnel experiment  Numerical simulation  Flow separation area  Aerodynamic performance

摘要:

为了改善串联式TBCC（Turbine based combined cycle）排气系统在低压比状态下的工作性能，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，并对含辅助活门的串联式组合喷管进行了实验研究，来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：辅助活门结构能够减少主流喷管外壁面的流动分离区范围和内流总压损失，有效地提高了组合喷管内推力。含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影响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气流量减少。

Abstract:

In order to improve the performance of the exhaust system of tandem TBCC under the condition of low nozzle pressure ratio， numerical simulation was carried out for two sets of tandem combination nozzles with and without auxiliary doors， and the tandem combination nozzle with auxiliary doors was also experimentally studied. The results show that the auxiliary door structure can reduce the range of the flow separation area on the outer wall of the primary nozzle and total pressure loss of internal flow to effectively increase the internal thrust of the combination nozzle. The combination nozzle with auxiliary doors can inject ambient airflow to reduce the range of flow separation area and bottom drag of the ejector 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 main flow nozzle pressure ratio reduces the degree of under-expansion of main stream at the throat of the primary nozzle. The sonic line moves downstream， and the mass flow rate of main flow decreases. Increasing the main flow nozzle pressure ratio or the secondary flow nozzle pressure ratio can increase the mass flow rate of ambient airflow injected by the auxiliary door. The distance of the inlet passage of the auxiliary door will affect 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 ambient airflow will be reduced.