Seal leakage Flow-affected Compressor Endwall and Fillet Profiling Design: Based on Optimization and Data Mining

In current research of axial compressor, flow control profiling designs for corner separation often overlook the influence of seal leakage flows, whose impact grows with increasing single-stage pressure ratios. Seal leakage flow alters near-wall velocity and modifies corner separation zone. Therefore, its effects should be incorporated into corner separation flow control design. This study investigates how seal leakage flows influence flow fields and separation at different rotational speeds. The results demonstrate that seal leakage flows substantially alter near-wall velocity distributions. The corner separation zones at 40% and 70% design speeds induce greater endwall loss than that at 95% design speed condition. To improve flow separation, the stator total pressure losses under near-stall conditions across multiple speeds are employed as the objective functions for multi-objective optimization of endwall and fillet profiling. Optimization analysis reveals that endwall profiling with suction-side protrusion and pressure-side depression near the front 20% axial chord region effectively controls leading-edge secondary flow intensity and improves corner flow. At 40% and 70% design speeds, the optimal profiling reduces total pressure loss by 7.28% and 8.96% respectively under near-stall conditions. Loss source analysis reveals that the seal leakage flow mixes with near-hub airflow and elevates entropy generation loss along its path. Furthermore, as rotational speed increases, the entropy generation induced by seal leakage in the near-hub region intensifies. Sobol sensitivity analysis further confirms the strong influence of endwall profiling at the 20% axial chord position on loss generation, validating the effectiveness of the optimized geometry.