Design and investigation on the combined two-stage waverider equipped with rocket and scramjet engine.

Aircraft employing the boost-glide-cruise combination flight mode can achieve longer range, but traditional single configurations struggle to achieve good aerodynamic performance. This paper introduces a novel design method for a combined two-stage waverider, aiming to enhance aerodynamic performance while considering the integration of different engines. After completing the boosting and gliding phases, the lower surface and engines of the first-stage waverider are discarded to promptly reduce aircraft weight, allowing for improved aerodynamic performance and more efficient propulsion during the cruising phase. The airbreathing cruising waverider is designed based on the principle of osculating cone at a fixed Mach number, combining the waverider forebody, afterbody, and stretched body to obtain a complete waverider configuration, equipped with a scramjet engine. The flow field corresponding to the wide-speed-range gliding waverider is reverse-designed using the upper surface of the airbreathing waverider, allocating different Mach numbers and shock angles for the conical flow field, obtaining the wide-speed-range waverider configuration through streamline tracing, and equipping it with a rocket engine. The two waveriders are combined by sharing the upper surface, while constraints on the inlet cross-section are provided to ensure no intersection or overlap of the lower surfaces. Subsequently, numerical simulations were conducted to analyze the aerodynamic performance of the two-stage waverider, verifying the validity of the design method. Finally, the configuration was applied to a boost-glide-cruise flight trajectory, revealing that the two-stage waverider designed in this paper is highly suitable for long-distance flight. Compared with a single-stage wide-speed-range gliding waverider with the same configuration, the range is increased by 147.8 %, further validating the rationality of the design method presented in this paper. • A separable two-stage waverider design based on boost-glide-cruise combined trajectories is proposed. • A wide-speed-range waverider and a fixed Mach number airbreathing waverider are employed to optimize performance. • It achieves a significant range increase in the cruising phase than the single-stage waverider. [ABSTRACT FROM AUTHOR]