Aerodynamic Optimization of a Single-Stage Axial Compressor with Stator Shroud Air Injection

The effects of stator shroud air injection on aerodynamic performance were investigated for a single-stage axial compressor. Multiobjective optimization of the air injector was performed to maximize the enhancements of the peak adiabatic efficiency and stall margin using three-dimensional Reynolds-averaged Navier-Stokes equations. The numerical results for adiabatic efficiency and the total pressure ratio were validated with experimental data for a smooth casing. The design variables were determined through a parametric study as the axial distance between stator leading edge and the injector, the radius of the injector surface curvature, the circumferential coverage of the injector, and the injection mass flow rate. The peak adiabatic efficiency and stall margin were selected as the objective functions. Kriging models were constructed using objective function values calculated at 45 design points, which were selected by Latin hypercube sampling to approximate the objective functions. The performances of two different optimization algorithms were compared. The optimization results showed that an efficiency-oriented optimum design presented an increase of 2.47% in the peak adiabatic efficiency when compared with the compressor with a smooth casing, whereas a stall margin-oriented optimum design showed an increase of 1.13% in the stall margin.