Upstream wake-passage vortex interaction in turbine cascade

The internal flow of turbomachinery is intrinsically unsteady, so investigating the unsteady interactions in turbine endwall region is meaningful for improving the performance of low aspect/high loading turbine. In this paper, the upstream wake-passage vortex interactions in turbine cascade were simulated by a 3-D unsteady viscous solver, and the flow mechanisms were analyzed. Numerical results indicate that periodic upstream wakes can enhance the radial vorticity of passage vortex, which increases losses. On the other hand, upstream wakes can suppress the streamwise vorticity development of passage vortex to some extent, which reduces losses. The combined unsteady effect in the endwall region depends on the balance of above two factors. At the calculation conditions of this paper, the unsteady losses finally increased.