Influences of the cavity leakage flow on shrouded stator performance at different inlet boundary layer shapes

Abstract

By using the validated numerical method to simulate the annular shrouded stator with the inter-stage seal cavity, the stator aerodynamic performance related to the cavity leakage flow was examined. The current study also indicated the interactions between the leakage flow and the mainstream. Discussions on the developments of secondary flow movement and hub corner separation were conducted, and the performances at different incoming boundary layer shapes were assessed using both the total pressure loss coefficient and the entropy-based loss coefficient. The results indicate that the cavity leakage flow creates a new vortex close to the leading edge of blade and is crucial to the passage vortex development and the concentrated shedding vortex size. At the same time, the cavity leakage flow weakens the transverse deflection of flow near the end wall and strengthens the three-dimensional flow effect. The two loss coefficients for the shrouded stator with seal cavity change little by thickening the boundary layer. The proper boundary layer skew as well as the interacted cavity leakage flow have stronger resistance to the deflection of the passage vortex and the transverse pressure gradient.