Propulsion and Flight Controls Integration for a Blended-Wing-Body Transport Aircraft

摘要

While operating at low airspeeds with nominal staticmargins, the controls on a blended-wing-body aircraft beginnto saturate, and the dynamic performance gets sluggish. Augmentation of aerodynamic controls with the propulsionnsystem is therefore considered in this research. Two aspects were of interest: namely, thrust vectoring and flapnblowing. An aerodynamic model for a large blended-wing-body transport aircraft with blown flap effects wasnformulated using empirical and vortex lattice methods and then integrated with a Trent 500 turbofan enginemodel.nTo enhance control effectiveness, both internally and externally blown flaps were simulated. For a full-spanninternally blown flap arrangement using intermediate compressor flow, the amount of engine bleed and the resultingnblowing coefficients were limited. However, even with a reduced bleed mass flow, the pitch control effectivenessnincreases by 15.9%at 85%fan revolutions per minute. For an externally blown flap arrangement using bypass air,nmuch higher blowing coefficients can be achieved. For instance, at 100%fan revolutions per minute, there is a 44%nincrease in pitch control authority at low dynamic pressures. The main benefit occurs during takeoff, where bothnthrust vectoring and flap blowing help in achieving early pitch rotation, reducing takeoff field length and liftoff speednconsiderably.With central flap blowing and a limited thrust vectoring of 10u0001n, the liftoff range reduces by 48%, andnliftoff speed reduces by almost 26%.