Effect of Geometric Changes in an Idealised Contacting Brush Seal Bristle Pack on Typical Key Performance Measures

In an effort to reduce gas turbine specific fuel consumption and to increase specific thrust, advanced sealing technologies have been deployed for the purpose of secondary air flow management. One such technology, the brush seal, provides a more compliant seal and hence improved leakage performance over the legacy industry standard, the labyrinth seal. It is known that brush seal geometry has a strong effect on the loading, deformations, temperatures and flows in the bristle pack. There is limited understanding of the complex interactions between the geometric variables. This paper describes a methodology for the modelling of an idealised brush seal domain based on Computational Fluid Dynamics. Bristle pressure and force distributions, temperature distributions and tip contact forces are presented. This methodology is used to examine the sensitivity of these parameters to the geometric input variables for a contacting seal configuration, using a Design of Experiments approach. Inferences are drawn from the results to determine which of the geometric parameters are most influential in brush seal pack flow-induced behaviour, and the strength of the coupling between these parameters and the key performance indicators.