A Flutter-Free Design Method for Axial Compressor Through Multidisciplinary Optimization Based on Directly Manipulated Free-Form Deformation

Blade flutter is a classical aeroelastic failure mode in aero-engine compressors and must be eliminated during the design process. A conventional approach to suppress flutter is adjusting the aerodynamic shape of the compressor blades. However, this method relies on the designer’s skill and experience. To address this limitation, this study proposes a flutter-free design methodology through multi-objective optimization combined with geometry parameterization technology. During the optimization process, the compressor aerodynamic shape is parameterized and deformed via the Directly Manipulated Free-Form Deformation (DFFD) technique, a three-dimensional geometry parameterization method that significantly reduces the number of parameters required to control blade deformation. The Non-dominated Sorting Genetic Algorithm II (NSGA-II) is incorporated into the optimization framework to automatically optimize the aerodynamic and aeroelastic performance of the compressor. This approach aims to mitigate flutter risk while enhancing aerodynamic efficiency. The proposed multidisciplinary optimization platform is applied to a transonic compressor, which comprehensively considers the influence of blade geometry, flow path and blade tip clearance. Results demonstrate that the optimized design completely suppresses flutter under the design speed, increases the isentropic efficiency at the design point by 1.43%, and maintains the surge margin essentially unchanged. These results validate the effectiveness and practicality of the proposed flutter-free design technology.