Aerodynamic adjoint optimization of turbomachinery with direct control on blade design parameters

Nowadays, the adjoint method has become a popular approach in the optimization of turbomachinery to further improve its aerodynamic performance. However, design variables in these adjoint optimization applications are generally not direct design parameters of blade (such as wedge angles or maximum thickness), making the geometric variation by adjoint optimization can hardly be re-extracted as the change of each design parameter. By giving considerations to the G1 continuity constraint of adjoint method on its parameterization method, this manuscript shows how to apply a parameterization method in 3D blade design process into adjoint optimization. Nearly all design parameters can therefore be treated as design variables in the adjoint method and then participate in the sensitivity-based optimization. Finally, a fitted Rotor 67 blade is optimized and the adiabatic efficiency is significantly improved by nearly 0.91%.