Control law design for variable cycle engine considering environmental indicators

Due to its prominent advantages in long-distance and long-endurance transportation, supersonic civil aircraft has become an important development direction for future civil aircraft. The concept of “green aviation” makes energy saving, emission reduction and noise reduction important optimization design objectives of civil aircraft, which naturally imposes corresponding requirements for its power plant. The traditional configuration power fails to realize the combination of low noise at takeoff, high thrust per unit for super-cruise, low fuel consumption rate and low emission index. Taking the dual-containment Variable Cycle Engine (VCE) configuration with Core Driven Fan Stage (CDFS) as the research object, this study examines the design method of steady state adjustable geometry control law considering key optimization design objectives such as the engine performance, jet noise, and NO_x emission. The research shows that the improvement in the first-containment variable cycle engine is the best way to improve the engine performance, and increase in the first culvert split ratio helps to reduce NO_x emission, while increase in the inner and second culvert split ratios facilites jet noise reduction. The design results are applied to the power unit re-optimization design of the first generation supersonic airliner Concorde. Compared with the baseline scheme, the supersonic cruise fuel consumption rate and the takeoff jet speed are reduced by 20.19% and 44.47%, respectively, enabling the takeoff noise index to meet the airworthiness requirements, under the premise of fulfilling the performance requirements of the aircraft.