Maximum-Thrust Nozzle Based on Height Constraints

Compared to conventional aircraft, hypersonic aircraft place a greater emphasis on the integration of aircraft and engines to meet their high-performance requirements. The design challenges of the nozzle are evident in the requirement of a significant area ratio between the inlet and outlet, as well as the need for the aircraft to have a compact overall size. In this study, the height constraint is directly incorporated into the maximum-thrust nozzle design method. A new method is proposed for designing nozzles under height constraints, taking into consideration the maximum thrust theory. Initially, a mathematical deduction of the condition in which the nozzle achieves the maximum thrust under the height constraint is performed. The method of characteristics is then used to develop a nozzle design that satisfies the height constraint. Subsequently, the influence of the design parameters on the design method is studied in a parametric manner. The results show that the Mach number scale and asymmetrical factors can affect the length of the nozzle's ramp and flap, respectively. These factors greatly influence the performance of axial thrust and lift within a specific height constraint. Compared to the traditional truncation design method, the proposed method increases the thrust coefficient by 11.93% and the lift by 138.45%.