Numerical simulations of upstream wake-tip leakage vortex interactions in turbine rotor

The internal flow of turbomachinery is intrinsically unsteady, so the research on the unsteady interactions in the tip region of turbine rotor is key to improve the performance of low aspect/high loading turbine. The upstream wake-tip leakage vortex interactions in a turbine rotor were simulated by a 3-D unsteady viscous solver. The flow diagrams of steady, time-averaged and transient results were analyzed. The results indicate that the unsteady interactions between the upstream wake and the rotor tip regions have changed the spatio-temporal evolution of the tip leakage vortex and the passage vortex, consequently leading to loss change. The tip leakage vortices and the passage vortices are separated into periodic perturbation counterrotating vortices. These counterrotating vortices move downstream along the tip leakage vortex path.