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Unsteady Numerical Investigation on Vortex Interaction between Rim Seal Purge Flow and Upstream Stator
Author(s): L. Zhou, Z. Wang, Yang Fan, J. Shi
Keywords: rim seal; ingress; egress; stator; vortex
To assess unsteady vortex interaction between the rim seal purge flow and upstream stator, numerical investigations were conducted under different purge flow rates. The vortex distributions for the stator and cavity were investigated and the interaction processes upstream and downstream of the cavity exit, in particular the vorticity change resulting from the ingress and egress, were analyzed. The results show that the intensity of hub passage vortex and hub trailing shedding vortex at stator exit is decreased as a consequence of enhancing blockage effects caused by the egress flow. However, from stator exit to downstream of the cavity exit, with the increment of purge flow rate, the reduction in the intensity of two vortices is weakened as the extrusion of egress flow thins their vortex tubes. The vortex inside the cavity is formed due to the combined effect of relative rotation of cavity walls and non-uniform circumferential pressure mainly imposed by upstream stator. The ingress leads the positive axial vorticity near the stator hub to ingest into the cavity and eject into the main passage due to the blockage of purge flow. In addition, the interaction between the ingress of the mainstream and purge flow produces local negative axial vorticity. The egress flow carries negative axial vorticity mainly produced by relative rotation of cavity walls and enters into the main passage near the rotating hub. Furthermore, the viscous shear between the egress flow and mainstream generates significant positive axial vorticity in the main passage.

Journal of Applied Fluid Mechanics

The Journal of Applied Fluid Mechanics (JAFM) is an international, peer-reviewed journal which covers a wide range of theoretical, numerical and experimental aspects in fluid mechanics. The emphasis is on the applications in different engineering fields rather than on pure mathematical or physical aspects in fluid mechanics. Although many high quality journals pertaining to different aspects of fluid mechanics presently exist, research in the field is rapidly escalating.