A steady and transient component-level mathematical model of a double bypass variable cycle engine (DBVCE) was constructed considering the effects of variable inlet guide vane and variable turbine nozzle area on component characteristics of compressor and turbine.Besides

the effects of the mode selector valve area on deputy bypass inlet air flow were also considered during the modeling process of DBVCE;two typical operation modes such as steady state and mode switching transient process were simulated.Results show that as the mode selector valve closes down

the surge margin of front fan block decreases obviously.When working in double bypass mode

the specific fuel consumption of DBVCE is lower

which is fit for subsonic cruise flight;otherwise

the specific thrust is higher in single bypass mode

which is fit for supersonic cruise flight.