Investigation on the Aerodynamic Characteristics of Nacelle Inlet Coupled with Fan Rotation Effect

As key aerodynamic components of an aircraft propulsion system, the design quality of the inlet and nacelle directly affects engine intake quality and overall aircraft stability. Nacelle design is trending towards greater compactness, making the coupling and matching between the inlet and fan increasingly critical. To investigate the mechanism by which fan rotation influences inlet aerodynamic performance, this study takes the NASA ROTOR 67 fan model as the research object and couples it with a specific civil aircraft nacelle model to conduct research on the effect of fan rotation on inlet performance. Through computational analysis of the flow field characteristics and aerodynamic performance of the inlet before and after coupling under cruise, high-angle-of-attack climb, and crosswind conditions, the results show that under cruise conditions, the inlet performance with and without the coupled fan is essentially consistent. Under high-angle-of-attack climb and crosswind conditions, the fan suction effect effectively mitigates open separation on the wall, disrupts the secondary flow vortices, and improves the exit flow field quality. After coupling with the fan, the total pressure recovery coefficient at the AIP plane shows significant improvement under both high-angle-of-attack and crosswind conditions. Fan rotation demonstrates a notable flow rectification effect under adverse inlet conditions, effectively enhancing inlet aerodynamic performance.