Multi-objective aerodynamic design optimization of a new engine intake electromagnetic wave blocker

A new engine intake electromagnetic wave blocker (EMWB) in a straight 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 setup are then established. Radar cross-sectional 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.