Scheme design and performance study of adjustable vector nozzle for wide-range hypersonic aircraft

In response to the urgent requirements for wide-range high performance, geometric adaptability of the exit, and efficient thrust vectoring capability of axisymmetric nozzles for wide-range high-speed aircraft, an adjustable vector nozzle and an internal-middle-outer three-ring adjustment scheme were designed. Numerical simulations were conducted on the nozzle under typical operating conditions, and the flow field structure and performance of the nozzle under different modes were analyzed. The results show that by adjusting the positions of the middle and outer rings through translational motion, the nozzle can adjust the exit area and has the thrust vectoring capability. In the non-thrust vectoring mode, due to the adjustable exit area of the nozzle, the overexpansion phenomenon at low nozzle pressure ratio is effectively alleviated, and the thrust performance is significantly improved. Compared with the fixed geometry nozzle, the thrust coefficient can be increased by up to 32.75%. In the thrust vectoring mode, the maximum vector angle larger than 10° can be generated at Mach number 7, while the thrust coefficient is still greater than 0.92. To further reduce the base drag of the nozzle at low Mach number, a flow control method for secondary flow intake was proposed, which can reduce the base drag by up to 78.5% by reducing the internal and external pressure difference of the secondary flowpath. Finally, a wind tunnel scale-down experiment was conducted. The experiment results were in good agreement with the numerical simulation results, verifying the effectiveness of the proposed design scheme.