Detailed experimental studies of flow in large scale brush seal model and a comparison with CFD predictions

A five times scale model of an engine brush seal has been manufactured The bristle stiffness and pressure were chosen to satisfy close similarity of t he relevant non-dimensional parameters, and the choice of parameters is des cribed. The comparison of pow characteristics for the model seal and an eng ine seal confirmed the non-dimensional similarity, Detailed pressure measur ements were performed within the bristle pack by employing hollow bristles. This novel measurement allowed insight to be obtained into the operation o f both clearance and interference seal.,. In particular, the measured press ure variation in the region of the bristle rips was significant. The deflec tion of the bristles was determined by comparing the bristle tip pressures with the static pressures along the shaft. Hence the compaction of the pack in this region was found directly. A numerical modeling of brush seals emp loying anisotropic flow resistance has been developed. Predictions Mere com pared with;he measured pressure distributions within the pack. This enabled sensible selection of the park resistance distribution to be made. Althoug h uniform anisotropic resistance throughout the pack gave reasonable flow r ate characteristics, the pressure distribution was not reproduced A variati on of resistance coefficient consistent with the observed compaction was re quired to give a solution comparable with the experiments.