A Multi-Physics Behavior Assessment Framework for Brush Seals: Effects of Geometry Parameters

Abstract

This paper presents a comprehensive coupled model to investigate the multi-physics behavior of brush seals. The integrated framework incorporates two components: a three-dimensional dynamic bristle model and a two-dimensional leakage flow model. The three-dimensional bristle dynamic model captures the slip friction and large deformation of the bristle pack under mechanical and aerodynamic loads. Additionally, this model can capture contact forces exerted by the rotor and backing plate and inter-bristle collision and squeeze forces, enabling accurate prediction of bristle deformation and the hysteresis effect in the rear part of bristle pack. The two-dimensional leakage flow model calculates the compressible flow field and the pressure distribution within the bristle pack to obtain a more accurate aerodynamic force around each bristle. Based on these two models, a fully bidirectional coupling can be established in the future: aerodynamic forces from the leakage models are incorporated into the dynamic bristle model, while the permeability changes due to bristle deformation and friction are fed back into the leakage flow models. An extensive parametric investigation is conducted to evaluate the influence of key geometric parameters. Specifically, the study examines the effects of fence heights, rotor incursion into the bristle pack, and bristle lay angle.