Analysis and Suppression of Thrust Trap for Turbo-Ramjet Mode Transition with the Integrated Optimal Control Method

An aircraft/engine integrated optimal control method is proposed for turbine-based combined cycle (TBCC) engines based on the Gauss pseudospectral method. The flight trajectory and TBCC law are obtained a TBCC-powered aircraft, “thrust trap” that occurs during turbo-ramjet mode transition further analyzed suppressed. Results show aircraft goes through phase using “climb-dive” trajectory, which strategy of applying gravity-assist temporarily reducing drag. Furthermore, engine adjusts at quickest rate to minimize thrust loss. With coupling law, minimum only 23% before transition, suggesting phenomenon. By decreasing time from 60 s 15 s, can increase 30%, phenomenon cannot be effectively When operating speed range turbine increases Ma2.5 2.9, will reach 80%, tends level off.