Performance Evaluation of Various Rim-Seal Geometries

Abstract

A numerical investigation has been performed to evaluate the performance of various rim seals in a gas turbine. Two performance functions of the rim seal related to sealing effectiveness and the loss coefficient of the main flow were analyzed for two rim-seal inlet velocities and three leakage fractions using three-dimensional Reynolds-averaged Navier–Stokes equations. The Spalart–Allmaras model was used as the turbulence closure model. The Reynolds number, based on the axial chord at the mainstream outlet, was fixed at 500,000. Computational results for the sealing effectiveness were validated by comparison to experimental data. To examine the effects of the rim-seal configurations on the sealing effectiveness and loss coefficient of the main flow, five different rim-seal geometries were tested. The results indicate that a newly designed rim seal, which includes the inner cavity attached to the rotor side and the narrow interaction plane between the mainstream and rim seal, shows the best performance in sealing effectiveness and loss coefficient among the five tested cases for most of the tested leakage fractions and rim-seal inlet velocities.