MAINSTREAM INGRESS SUPPRESSION IN GAS-TURBINE DISK CAVITIES

The sealing characteristics of an air-cooled gas turbine disk cavity h ave been studied using laser sheet flow visualization. Experiments wer e performed on a simplified half-scale model of an actual gas turbine disk cavity. This type of rotor-stator geometry with a double-toothed- rim (DTR) seal at the outer periphery and a labyrinth seal at the inne r periphery of the cavity has been tested for its ability in preventin g ingress of hot mainstream gases. The results show good agreement wit h previously esimated design data. Experiments were conducted for vari ous labyrinth seal flow rates and rotational Reynolds numbers up to 1. 52 x 10(6). The effects of rotor eccentricity on minimum purge flows h ave also been discussed.