Predicted performance of brush seals: Porous medium versus resolved bristle matrix and comparison with experimental data

Authors

A.O. Pugachev - Technical University Munich, Germany

Abstract

The paper compares two theoretical approaches for modeling gas flow through brush seals. In the first approach, the bristle pack is represented as a porous medium. The resistance to the flow through the bristle pack is described by viscous and inertial resistance coefficients defined in a bristle streamwise direction and directions normal to bristles. In the second approach, several tens of individual bristles representing the bristle matrix segment are modeled directly. In contrast to the model based on the porous medium approach, the model with the resolved bristle matrix provides more accurate local flow characteristics but at the expense of complexity and high computational costs. Two brush seals are studied numerically to compare two theoretical approaches in terms of leakage, pressure and velocity distributions. In addition, the predicted results are compared with available experimental data on leakage and the axial pressure drops for various operating conditions. The capability of both approaches to predict brush seal performance is discussed in detail.