| 초록 |
Designing physically feasible and fuel-efficient trajectories for dual-mode scramjet vehicles is challenging because propulsion performance, operability limits, and aerodynamic loads vary sharply across the ram–scram flight envelope. Many existing trajectory optimization studies relied on simplified or static propulsion representations, and key operability effects such as inlet unstart and blowout were examined but not enforced. As a result, the underlying coupling between propulsion and aerodynamics was only partially captured, limiting the assessment of feasible hypersonic trajectories. This study develops a Sequential Convex Programming (SCP) framework that combines mode-specific propulsion surrogates with state-dependent operability constraints. The formulation allows stable trajectory optimization across the ram to scram transition, even near tight propulsion and aerodynamic limits. A design-of-experiments (DOE) campaign shows that enforcing state-dependent operability constraints increases the number of feasible cases and improves solver convergence across sampled conditions. In the 100-case DOE (66 cases feasible within the dynamic pressure limit), the proposed solver increases the feasible count from 21 to 29 (38.1%) and reduces the mean iterations to feasibility from 5.238 to 3.552 (32.2%). Fuel-optimal analyses indicate that trajectory efficiency is strongly influenced by the acceleration margin available at ignition. When this margin is limited, the vehicle cannot sustain the required thrust and fuel use during the climb. Relaxing the lower bound on dynamic pressure allows altitude to be gained earlier, which improves aerodynamic and propulsion margins later in the trajectory and reduces subsequent fuel consumption. In some solutions, the fuel-optimal trajectory exhibits alternating powered and unpowered segments. Across these solutions, the vehicle reduces fuel use by trading thrust, drag, and altitude along the flight path. The results indicate that efficient hypersonic flight depends on maintaining operability and dynamic-pressure margins while managing mechanical energy, rather than on uniformly reducing fuel flow.
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GISCIENCE & REMOTE SENSING, v.63, no.1, 2026-12