Contact Force Measurements Under a Brush Seal

Abstract

This paper discusses results of experiments carried out to measure the bristle contact force of a brush seal on a shaft. Two separate experimental techniques were used: i) indirectly through torque measurements and ii) directly using a force blade located under the bristle tips. The tests were conducted on a non-rotating shaft having a nominal diameter of 122 mm, with static radial interferences of 0.4, 0.2, 0.1 and 0.05 mm; and for the range of pressure ratios 1 to 4.5. The experimental results obtained from these measurements are compared with predictions from a simple theoretical model. Although there are some large differences, the experimental results do show some agreement with the theoretical predictions. However, both this current simple theoretical model and the experiments have their limitations. Despite these shortcomings, the experimental results are considered to support the qualitative value of the current theoretical model.