Improved carbon fibre brush seals for high pressure applications

Abstract

This article describes the performance of carbon fibre brush seals for high pressure applications whilst addressing the importance of the robustness of the brush seal structure. Brush seals are usually manufactured through crimping of the fibre pack between two annular aluminum fine structures. The simplicity of this setup and low bulk compromise however the life service of the brush seal because of uprooting. Here, assembled brush seals with a non-conventional arrangement, with the fibre pack being oriented against the flow direction, could be tested for the first time at differential pressures up to 10 bar. They exhibited remarkably low air consumption. This was however achieved at the expense of high friction, whose effects have to be mitigated to avoid seal destruction. Brush seals were also submitted to endurance testing under lubricated conditions at low pressures, and after 300 hours, the performance degradation was negligible. The brush seal adapted assembly successfully prevented uprooting arising to fibre friction combined to high rotational speed, and renews promising prospects in the use of carbon fibres for challenging sealing conditions.