基于二次流喷射的并联式TBCC 排气系统性能提升技术研究

Base on CFD, the flow characteristics of over-under TBCC (Turbine Based Combined Cycle, TBCC) exhaust system was analyzed. A method to enhance the exhaust system performance by injecting high pressure secondary flow into the down wall of turbo-engine nozzle was proposed. And the effects of secondary injection on the performance, e.g, thrust coefficient and thrust vector angle were investigated in different flight Mach number. Results show that secondary injection produces bow shock, which can generate new flow separation region interaction with ramp of nozzle. Bow shock improve turbo-engine nozzle and ramjet nozzle pressure distributions, thus improve nozzle thrust and thrust vector performance, and obviously improve over-under TBCC nozzle performance at subsonic and transonic condition, which makes the axial thrust coefficient increase by 7.34% and thrust vector angle increase by 12.76°.