Effects of labyrinth cavity angles and non-axisymmetric end wall on the performance of the shrouded stator at different inlet boundary layer thicknesses

The interplay between leakage flow and secondary flow markedly impairs the aerodynamic efficacy of shrouded stators within axial compressors. However, the synergistic influence of inlet boundary layer thickness, cavity angles, and non-axisymmetric end wall contouring remains insufficiently understood. This study employs numerical simulations to systematically investigate the underlying mechanisms by which these factors influence the flow in a high-pressure compressor cascade, while innovatively integrating variations in labyrinth cavity angles with non-axisymmetric end wall design to enhance stator performance. Results reveal that thicker inlet boundary layers increase total pressure and entropy loss coefficients by over 12.03% and 10.71%, respectively. Notably, increasing rotational speed leads to a reduction in the entropy loss coefficient until the escalating losses caused by temperature gradients begin to offset this benefit. Among five cavity angle designs, structure 4, featuring an inlet angle opposing the mainstream and an outlet angle aligned with it, achieves optimal performance at 0 rpm by minimizing leakage and mixing losses. The incorporation of non-axisymmetric end wall with structure 4 further reduces total pressure and entropy loss coefficients by 5.09% and 2.66% at 0 rpm, respectively. However, its effectiveness diminishes at higher speeds due to overlapping effects with circumferential momentum. This study provides a pioneering exploration of the coupled control mechanisms involving cavity angles and non-axisymmetric end wall design, offering valuable insights for enhancing stator efficiency under complex operating conditions and establishing a theoretical foundation for advanced turbomachinery design.