Periodically Cruising Hypersonic Vehicle With Active Cooling: An Optimal-Control Based Design Approach

Periodic cruise has been proven an effective trajectory to conserve fuel and alleviate aerodynamic heating for hypersonic cruise vehicles (HCVs). This work studies how to adopt an HCV with active cooling to periodic cruise. In this adaption, payload capacity is to maximize, whereas the cooling requirement is to reduce. The differences in requirements for subsystems between periodic and steady cruises have been made clear. The results indicate that periodic cruise principally transfers the burden of thermal protection to the structure, and that periodic cruise is more effective to trade payload capacity for larger reduction of cooling requirement. Afterward, impacts of design parameters of the vehicle on payload capacity and cooling requirement have been discussed. The results indicate that insulation thinner than 3 mm, a planform loading lower than 220 kg/m
²
, or a large engine is not suggested for the vehicle studied herein. This work figures out the correlation between design parameters of vehicle and features of periodic cruise trajectory. It could help to improve the feasibility of periodic cruise for a hypersonic vehicle, which is significant for realization of the long-range hypersonic cruise.