05 - Propulsion and Energy
INLET OPTIMIZATION DESIGN OF A BOUNDARY LAYER INGESTION PROPULSION SYSTEM
X.K. Ma¹, H.C. Yang¹, K. You¹, R.B. Zhu¹, Z.L. Chen¹; ¹Northwestern Polytechnical University, China
Boundary Layer Ingestion (BLI) propulsion systems can significantly improve aircraft propulsive efficiency, but severe inlet distortion remains a critical challenge. To address this issue, this work develops an adjoint-based aerodynamic optimization framework for BLI inlet design. A fan body force model (BFM) is incorporated into the optimization process to account for propulsion–airframe coupling effects with substantially reduced computational cost. The proposed methodology is first validated using the IFCPT S-duct benchmark case, achieving reductions of 27.4% in the circumferential distortion index (CDI). Subsequently, the framework is applied to the optimization of a BLI propulsion system integrated into quasi-periodic fuselage of a blended-wing- body-based configuration under the operating condition at Mach number 0.5 and fan rotating speed of 90%. Optimization results show that the optimized inlet effectively suppresses flow separation and secondary-flow structures inside the duct, resulting in a more uniform fan-face flow field. Compared with the baseline configuration, the optimized design achieves approximately 13.4% reduction in the distortion index DC60, approximately 0.5% improvement in total pressure recovery, and significantly reduced swirl distortion at the fan face. Flow-field analysis indicates that the improved aerodynamic performance is primarily associated with the redistribution of adverse pressure gradients and the enhancement of flow attachment throughout the duct. The present study demonstrates that the proposed adjoint-based framework combined with the fan body force model provides an efficient and effective approach for the aerodynamic design and optimization of BLI propulsion system inlets.
DOI: 10.71945/icas2026_0906