Effects of geometrical parameters on bristle mechanical characteristics and deflection behavior of brush seals in gas turbine engines

Abstract

Within the engine air system, the sealing is pivotal for augmenting engine thrust and efficiency. The brush seal, a contact-based sealing structure, exhibits commendable sealing efficacy. Nevertheless, the supple bristles tend to slip circumferentially in swirl inlet, diminishing the seal's stability and thus constraining its applicability. This study employs a fluid–structure interaction approach to initially dissect the flow field dynamics within the bristles in swirling conditions, examining the aerodynamic behavior across various bristles and their consequent motion and deformation. Leveraging the Design of Experiment method, typical geometric variables of brush seals, such as the diameter, length, inclined angle, rows, radial clearance of bristles, and the spacing between bristles, are scrutinized, and their influence on aerodynamic force distributions on the first row of the bristles and the interplay among these parameters assessed. It was observed that under the swirl inlet imposed, the first row of bristle pack experiences diminished axial forces compared to no-swirl. The diameter of bristle emerged as a primary factor impacting axial aerodynamic force, contributing 33% of the force, and there exists a linear correlation between diameter and axial aerodynamic force. Notably, the interplay between bristle diameter and inclined angle significantly influences axial forces and bristle deformation. The critical factors influencing the normal aerodynamic force acting on the bristles were identified as the spacing and diameter of the bristles, with respective contribution rates of 27.4% and 27.3%. A linear escalation in the normal aerodynamic force is seen with increasing spacing and diameter. Additionally, a substantial inverse relationship between diameter and inclined angle was discerned.