The Transient Performance of FLADE Variable Cycle Engine During Mode Transition

Variable cycle engine with FLADE, abbreviation for Fan on Blade, is one of the research focus for future military and civilian aircraft power plants, showing outstanding performance advantages. A FLADE calculation method was established by calculating bypass flow and inner flow independently, to developing a steady-state performance simulation model for double bypass variable cycle engine with FLADE. The dynamic equations that can reflect the rotor inertia effect and component volume effect were added, to developing a transient performance simulation model. The transient characteristics of mode transition were analysed during opening/closing FLADE duct, putting emphasis upon the influence of geometric parameters adjustment and its different combinations. The results indicate that the mode transient characteristics of FLADE variable cycle engine are only influenced by FLADE vane angle and FLADE nozzle area, which should be increased or decreased synchronously. Both of the engine bypass flow and core flow are affected by opening or closing FLADE duct slightly.