Coupled optimization of airfoil shape and configuration parameters of highly loaded compressor tandem cascades

Abstract Tandem cascade is an effective aerodynamic design approach for suppressing boundary layer separation and improving the stability margin. To obtain subsonic tandem cascades with excellent performance and establish corresponding general design principles, this paper performs a multi-condition coupled optimization on both the airfoil shape and configuration parameters of tandem cascades. The coupling optimized tandem cascade (OPT_11VAR) is compared with the configuration-only optimization results (OPT_5VAR). Comparative analysis shows that compared to the original tandem cascade, the total pressure loss coefficient ( ω ) for OPT_5VAR is reduced by 18.0% at 4° incidence angle while achieving an 8.9% increase in incidence margin. Interestingly, the optimal configuration parameters for OPT_11VAR differ from those of OPT_5VAR, demonstrating that airfoil shape significantly influences configuration optimization. Furthermore, OPT_11VAR achieves enhanced performance compared to OPT_5VAR, reducing ω by 29.8% at 4° incidence angle and increasing the incidence margin by 14.5%. This study proposes new design criteria for tandem cascades and demonstrates the interdependence between airfoil shape and configuration parameters.