Effect of a rib on rim seal performance

The effect of a rib installed in a rim seal on sealing effectiveness was investigated using three-dimensional Reynolds-averaged Navier–Stokes analysis. A parametric study was performed for a single square rib installed on the surface on the rotor side. A total of 12 cases were tested with different heights, widths, and locations of the rib. The Spalart–Allmaras model was adopted as a turbulence closure model. The Reynolds number based on the axial chord of blade was 500,000 at the mainstream outlet. Ratio of the mainstream outlet velocity to mainstream inlet velocity was kept constant at 3.10. The sealing effectiveness was selected as the performance parameter. Installation of a rib in the rim seal enhances sealing performance regardless of the dimensions and location of the rib, although the effects are relatively small in some cases where the rib is located far from the surface of the rim seal on the rotor side.