Research on starting modeling and control law of variable cycle engine
To research the starting control law of double-culvert variable cycle engine,based on the modeling method of component,the method of air mass flow balance was used to establish corresponding common working equations,and the double-culvert variable cycle engine starting model was established by considering the processing method of variable geometry characteristics for adjustable components and the low speed characteristic extrapolation method of the rotating components.Through using single factor analysis method,it changed single geometry adjustments,including the guide vane angle of fan,core driven fan stage(CDFS)and compressor,the throat area of low pressure turbine,the area of front variable area bypass injector(FVABI),rear variable area bypass injector(RVABI)and exhaust nozzle,and studied the influence on the starting performance of engine to obtain the influence matrix of geometric variables.Based on this,starting control law was researched.Research showed that in this starting control law,the guide vane angle of fan and CDFS,FVABI and nozzle were kept at closed position,and the throat area of low pressure turbine kept at the max position,whilst the area of RVABI and the guide vane angle of compressor decreased with the increase of rotation speed.Test result showed that,the starting control law was correct and feasible,and variable cycle engine started successfully.The conclusion provides a reference for variable cycle engine control law and starting performance design.