Multi-objective Aerodynamic Design Optimization of a New Engine Intake Electromagnetic Wave Blocker

A new engine intake electromagnetic wave blocker (EMWB) in astraight duct configuration is proposed as an alternative to S-shaped air intake ducts for reducing radar and infrared signatures of aircraft. A computational fluid dynamics model is developed and verified against an existing S-duct air intake study. Ten geometric parameters of the baseline EMWB are selected as design variables for a multi-objective optimization study. The design space is extensively explored with 68 configurations, applying the constraints of pressure recovery (PR) > 0.97 and distortion coefficient (DC60) <0.06. This process yields 16 feasible designs, from which the best performing model in terms of PR and DC60 is selected as the optimized EMWB. The electromagnetic model and experimental set-up are then established. Radar cross section measurements of the optimized EMWB model demonstrate significant improvements: aerodynamic performance is increased by 8.1% for PR and 14% for DC60, while the radar cross section is decreased by 51%. These results suggest that the optimized EMWB in a straight duct configuration offers a promising alternative to S-shaped ducts for reducing aircraft engine signatures while maintaining aerodynamic performance.