Analysis of brush seal bristle stresses with pressure-friction coupling

Abstract

With their superior leakage performance brush seals are used in many demanding sealing applications. In recent years, they found ever increasing use in ground based large industrial gas and steam turbines replacing labyrinth seals. As the applications become more demanding, seal designs are pushed to their limits. The knowledge of brush seal bristle stresses is essential to determine seal pressure carrying capability and amount of creep for high temperature applications. Seal manufacturers continue to rely on their experience and simple models based on beam theory in order to develop the required robust seal designs. Although some analytical formulations are developed over the years, pressure-stiffness coupling and its effects on bristle stresses deserve further study due to complicated frictional bristle interactions. In order to explore brush seal bristle stresses with frictional effects, this paper presents a study using a 3-D finite element analysis. A maximum bristle stress relation is derived based on statistically designed experiments. Model accuracy is determined through verification simulations. A discussion on the effects of design and loading parameters on maximum stress is also included. © 2013 Elsevier B.V., All rights reserved.