Adjoint optimization of a multi-row transonic compressor based on an extended free-form method

The adjoint method plays an important role in the aerodynamic design of turbomachinery. However, most optimization objects are only local parts of the fluid domain in turbomachinery, such as blade or end-wall. In this study, a novel parameterization method is adopted in the adjoint optimization framework to merge all design spaces together and then a typical multi-row compressor, Stage 35, is optimized by the in-house adjoint optimizer, TurboSim_un. The adiabatic efficiency of STAGE 35 is improved by 1.7%. Results show that the intersection of shock wave and boundary layer is weakened and the performance in mainstream is significantly improved.